Architect is definitely "same sort of creature" as Corypheus. By their nature, they're same, but I have noticed some interesting differences.
First of all;
Architect uses the Warden's lack of ancient darkspawn and Magister lore to escape;
Dialogues between Architect and Utha suggest that Utha was always Architect's escape plan. Utha is a former Grey Warden that Architect convinced to join his cause during the time he captured Maric, Duncan and Fiona. If you remember the dialogues between Architect and Utha you'll realized that Utha has always been willing to give her life to save Architect. That is why she was always near the Architect whenever the Warden was also nearby. So, Architect possessed the dead body of Utha, who is now a soulles tainted vessel. Since the Warden joined the Order of Grey short before the Battle of Ostagar, he didn't know about the Ancient Tevinter Magisters/Archons and Anciend Darkspawns. Similarly, Corypheus possesses a dead Warden in the Arbor Wilds when his body gets destroyed. And yes, Architect once captured and caged King Maric the Saviour, Warden Commander Duncan and Grand Enchanter Fiona. And all three of them could be either dead or used for experiments for the rest of their lives by Architect if Loghain hadn't arrived with an army to save them.
Architect was the one who started all the previous Blights;
In Awakening, it is also revealed that Architect started the Fifth Blight with a failed attempt at making Old God Urthemiel his disciple. He seems to know a great deal about the taint and darkspawn magic. In DAO: Awakening, Warden fights darkspawns and "Dragons". Architect was trying to tame/control Dragons since they're the closest beings by their nature to the Old Gods. The reason Architect wanted Grey Wardens was to have their blood, which developed immunity to the taint after the Joining. In Dragon Age Origins, when Warden asks Riordan why are there such a long periods of time between each Blight, Riordan says that he is not surprised it takes centuries for Darkspawn to find the Ancient Prisons and reach to the Old Gods, he is surprised that they actually manage to find them at all, without someone to lead them. Architect fills the hole right here. He was obviously not asleep/imprisoned like Corypheus and he was around for quite a long time when the Warden encountered him, since we know Architect captures Maric, Duncan and Fiona and that was long before the Blight. So I think Architect started all the previous Blight trying to make Old Gods his disciples, not only the Fifth Blight.
Why would Architect want to control Old Gods so badly?;
The same reason Corypheus wanted to go to the Black City to turn his Red Lyrium Dragon into a true Archdemon. What Architect wants and what Corypheus wants are the same things, only their methods are different. Conductor's dragon was just a High Dragon that he fed Red Lyrium after infusing himself with Red Lyrium in order to be able to control it. If Corypheus succeeded in DAI and reached to the Black City, his Red Lyrium Dragon would have turned into a true Archdemon. Why Cory wants it and why does he think that would make him God? Because whoever controls a true Archdemon, also cantrols the whole Darkspawn Horde. Darkspawns are much greater in number than any all other armies of Thedas combined and that is why the only way to stop a Blight is to slay the Archdemon. First Blight is the perfect example for that. Lasted for more than a century and completely destroyed and desolated Anderfels and ruined Tevinter. And since Corypheus and Architect has the ability to transfer their souls to the soulles tainted vessels (like darkspawn or dead wardens) or willing tainted vessels who has soul (like a willing grey warden), they could technically become immortal. So their goal is = Immortality + An Army that could conquer whole Thedas. So in short, Corypheus wanted to turn his Red Lyrium Dragon into an Archdemon while Architect wanted true Old Gods to be his Archdemon.
How are they different then?;
Corypheus is drawn to the Black City like a moth to a flame and Architect is drawn to the Old Gods the same way. It doesn't matter how many times they fail, how terrible consequences they have to face, they do the same thing over and over again. This is strange because if they were in the Black City together, then why are not both attracted to the Black City? Perhaps Architect didn't go to the Fade with the other Magisters? Corypheus doesn't feel the presence of Dumat - he hears no whispers, no commands (see Corypheus' Memories and DA Wiki for more information). But he is the High Priest of Dumat and we know it was Dumat who whispered to the Ancient Tevinters. There is one more possibility, Dumat may have spoken to the "First Priest of Dumat"(Usually Archons) rather than the "High Priest of Dumat"(Corypheus).
There are some interesting Information we know about "Archon Thalsian", "the first person known to wield blood magic", "who is also the First Priest of Dumat" "claims to learn the art after personally communicating with Dumat". We know that it was Dumat who told the darkest secrets of Blood Magic to Ancient Tevinters and that was how Magisters were able to go to Fade in flesh. So, I think Architect is an Ancient Tevinter Archon, not Ancient Tevinter Magister. That would explain "the same sort of creature" part. Another detail to reinforce this idea is, Architect's appearance. Corypheus wears some sort of a deformed robe while Architect wears something like "crown". See the picture in the spoiler below.
That would also explain the title "Architect". Remember the Architect and his personality. Extremely smart, knows a lot about the taint, blood magic and magic in general, deceiving. Pulls the strings of others from the shadows and changes the course of history (by starting Blights and capturing important figures like Maric, Duncan, Fiona and the Warden-Commander). Also, doesn't like risking himself personally. He tried to avoid fighting the Warden and even so he had a back-up plan in case the fight may be inevitable. We know that Ancient Tevinters "built" a ritual system with huge amounts of lyrium and lyrium is the cause of their deformations. Architect, their archon and the First Priest of Dumat ordered his Magisters to go to Fade and claim the Heavens. Archon Thalsian is called "the Architect" probably because he "built" this ritual system, this "stairway to the heavens" since we know that Dumat whispered to Archon Thalsian and taught him how to go beyond the Veil and reach to the Fade. He probably did not go to the Fade himself to not risk himself. He is a bit too smart to walk the Fade in flesh so he ordered his Magisters to go instead and gave the duty of leading others to the High Priest of Dumat, who is known as Corypheus/Conductor. Dumat probably planned that the Magisters would go to Black City and bring back the taint of the Black City so that Dumat would be freed of her prison and rise as an Archdemon. Corypheus also says that the Golden City was already blackened when they went there. So, they got tainted in the Black City and started to spread the taint when they came back. Architect probably expected them to either succeed and return safely or not return at all. When they came back, they probably started spreading the taint by Architect. Dumat probably whispered to the Archon Thalsian again and told him to free her from the prison and offered to share her power in return.
Another interesting detail; Architect's personality is just like "Flemeth's" isn't it? Flemeth was just like the Architect in that sense. She is intelligent, knows a lot about the taint and magic and she's deceiving. She changes the course of the history (saving the Warden, for example affected the fate of whole Thedas). She tried to avoid fighting the Warden and took precaution in case the fight might be inevitable (tricked Hawke into helping her revive herself with that amulet), just like the Architect. Flemeth has the soul of Mythal and Dumat is known to be the OG counterpart of Elven God Mythal. That is also another interesting coincidence. I bet Architect knows who and what Flemeth is and works for her/Mythal. It is said that Dumat, the Old God of Silence only speaks to the worthy and that would explain why Flemeth/Mythal/Dumat communicates with the Archon Thalsian/Architect but not with Corypheus. That is why when Corypheus begs Dumat for power, he doesn't get any answer other than silence, at the end of DAI.
Wiki page about Archon Thalsian: http://dragonage.wik...m/wiki/Thalsian
Architect and his crown.
For those who don't like reading long texts. In short: Architect may be the Archon Thalsian. So he is not an Ancient Tevinter Magister, but he is the Archon of Ancient Tevinter Magisters.