The Maker fills the requirement for a First Cause. Even the elves don't believe their Creators/Evanuris actually created the world; nor it would appear did the ancient human cultures. The world didn't spontaneously come into being; hence the need for a Maker.
According to one of the older bits of the Chant, which sounds an awful lot like a combination of the beginning of Genesis and the Gospel of St. John; in the beginning there was nothing but silence, then the Maker spoke the first Word and this became "all that might be: Dream and idea, hope and fear. Endless possibilities." So effectively the entire history of creation was contained in that first Word. Basically the Maker is all in all, which actually ties in with Leliana's belief in Origins that the Maker is there in the beauty of the world and she can hear him in the wind in the trees, etc, so never absent but not acting within it since all he intended has already been done. He is present in everything.
It is after this that the creation story starts to contradict itself. Thereafter the Maker started creating beings to inhabit this new creation which I take to be the Fade, starting with the spirits, and says to them "To you I give dominion over all that exists. By your will may all things be done." So at this point he actually seems to have stated that he is not going to get involved and has given over the running of his creation to the spirits. Then when the spirits do nothing but standing around happily praising him, he thinks better of it and decides to create a more permanent realm, Thedas, and creatures within it with the ambition to do something creative with it. It says he set the two realms apart but doesn't actually say there was a Veil and the stories in the ancient library suggest that the two were both separate and yet conjoined.
From then on the Maker acts more like the other gods that appear in the story. He watches to see what wonders his children will create. Gets angry when his firstborn, the spirits, start doing something and actually try and take dominion over all that exists (he presumably forgot to mention to them that would only apply to the Fade). He casts the presumptuous spirits into the earth simply for daring to try and be gods to the earthly creatures because this actually occurs before they give Tevinter the secrets of darkest magic. According to the Chant the human tribes had returned to worship of the Maker but constantly warred among themselves and one king wanting to get an edge over the others listens to the dreamer, Thalsian, and starts making burnt offerings of oxen and horses (again sounds more like our Old Testament) in return for the knowledge and power to defeat his enemies. This is said to come from a demon of the Fade but if it was the old gods beneath the earth speaking then they are no longer in the Fade. (As I say the Chant is full of contradictions). The king had previously asked the Maker for signs of victory by getting his Oracles to consult the stars, drink blood of unclean beasts (it suggests wyverns) in order to seek counsel from the Maker. So it would seem that the notion the ancient tribes had of the Maker was one where they had to perform strange rituals in order to get his attention and in this case he did respond but told the king that "no victory was his to claim". Which is why, since the king wouldn't take no for an answer, he turned elsewhere for advice.
Still it is clear from this that the Maker didn't turn away from mankind for their initial worship of the old gods because he apparently still kept up a dialogue after they had been imprisoned beneath the earth. When the advice of the demon makes the first king stronger than his rivals who still worship the Maker and the Maker doesn't intervene to prevent the death toil from rising, when faced with almost certain defeat, the last king turns in desperation to a similar source of advice to his rival. This gives him the edge in battle and enables him to resist his enemy. It does seem odd that this king at least was perfectly willing to worship the Maker but didn't really see the point of continuing to do so when the Maker seemed willing to let him and his people perish, yet the Maker failed to intervene in this case but apparently took up the cause of Andraste. Did Damertes just not have a very good singing voice?
So I'm tending towards the idea that, just as was always maintained by the writers, we will never be given conclusive proof of the Maker's existence and anything that appears in the myths and legends of the people of Thedas says more about their faith and beliefs and reflects a memory of actual events that occurred in the past that had nothing to do with activity by the Maker. For example, ancient gods were imprisoned at some point, but not by the Maker but other more powerful creatures who were regarded as gods by their own followers. Most "gods" within Thedas were probably spirits that either spoke from the Fade or took more tangible form in the material world. The Golden/Black City has less to do with the Maker and more to do with an ancient city that once existed in both the Fade and the material world and was a seat for the gods. (I'm going with Arlathan at the moment) When the Veil was created it shattered and the bit trapped within the Fade was closed off to visitors. A vision of Drakon showed it to have 7 gates. This would correspond to one for each old god. There is something bad there; we were told back in Origins that even powerful demons avoid it. I believe that whatever the truth is about the Black City, this has more to do with the actions of Fen'Harel than the Maker.
According to the memory of his servant we find in the Fade, Corypheus seemed to have been becoming increasingly desperate because he was cutting himself ever more frequently, presumably to try and contact Dumat and getting no answer. In JoH there seems to have been a similar panic among the followers of Razikale. The assault was originally to try and find out why this was. Corypheus seemed convinced that getting to the Black City will confer godhood upon him; may be there is a source of power there or may be simply the fact he could get there and not be coughed back out again would have been a sufficiently impressive deed to merit godhood. The fact that he kidnapped the Divine and used her as part of a sacrifice to achieve his aims would suggest that he realised he needed to undermine the current dominant faith in Thedas to achieve his aims. The Chantrys (both Black and White) believe the Golden City was once the seat of the Maker, so it follows if you can prove it empty and the Maker takes no action, you have usurped his place. It doesn't prove conclusively there is no Maker, simply that he is not getting himself involved and so there is little point in appealing to him for help.