I have not started playing yet... but is there anything that fills that void in DAI? If there is a lack of depth in the area of companions and skills & abilities, does some other part of the game make up for it? Some other activity that provides a roleplaying experience in another way?
I've seen people saying they are finishing the game in 2-3 days time. Is there really a lack of overall depth in the way you are describing, was that 150 total hours just a crock of ****?
Well - It really depends:
If you do any and all side-quests (well, if you can call collecting stuff, tagging (claiming) stuff etc. quests -.-), then no, you will not finish in 2-3 days (I am playing since Monday and I don't think I am half-way through yet...I don't know - I haven't seen an indicator showing how much there's left)...the thing is:
I would rather have less tedious things to collect (I want to see as much as possible on the first run - of course excluding the mutually exclusive things like siding with the mages or templars - can't have it both ways it seems) and more good storytelling and narrative - even if it meant (a little) less playtime (!)
I am going to repeat what others have already said:
I would have liked DA:O with new graphics (not that I would not have gotten the game if it used the DA:O-Engine - I am not that much a graphics-****** to leave out an RPG (if it is good - note: DA:I is not really bad, but it's not on the same level as DA:O!) if it looks a little dated!), another story (hell, I quite like the idea of the Inquisition and the chantry being destroyed and people having a crisis of faith etc. - the problem is, that many things that could make this game great are not as good as they should be - like the upgrade system for Skyhold and your Inquisition: You need to collect Materials - reminds me of Mass Effect 2 (the ship upgrades for the Normandy) - instead of doing it with really thought out quest-chains that would give the game more "meat" (it feels like it lacks substance IMHO - like a gnawed bone with only a few tiny scraps of meat still clinging to it)...an example: You want to upgrade your Inquisitions weapons - ATM you need to collect crafting materials and then sign of on a requisition, while IMHO you should need to recruit a smith first (maybe the smith has an issue you have to solve first - like in DA:O the smith in Redcliff who wanted you to save his daughter - before he (or she...a female smith, like Charsi from Diablo 2 would have been nice) wants to sign on and give you the follow up quest(s)...yes there should be some collecting of materials, but only of really important ones IMHO, like dragon bones (stuff that not every merchant would have available - rare things) - I hate having to farm in offline-games...it's no fuckin' MMO -.-) and new and interesting characters (note: yes, a few of the champions are interesting - but many are not...and some should have an opposing viewpoint present (like Vivienne singing the virtues of the circles - there should be another mage there that has been abused for example and really hates the circle and the chantry (note: Doriane does not count, he is from Tevinter and thus a really free mage...though he agrees that mages should not be locked up
)), I mean there's no really good banter because the characters agree with each other too much IMHO (note: that's something DA:O and even DA2 did well - Morrigan and Alistair for example or Fenris (Mage hate) and Anders (mage love to the point of corrupting a spirit and becoming a terrorist!) or Isabela (love of sex, loves being sassy) and Aveline (very pious, conservative etc.))...they don't tend to dissagree -.- which makes them seem bland in comparison to the other two batches of DA-Characters we have had 
Note: DA:I is not a bad game, but it suffers from too much ambition (re-inventing the wheel - again) and not covering its bases (things DA:O - and even DA2 - did well), things we do expect from Bioware (maybe they can't do it anymore? - I mean DA:O, ME1 and 2 and KOTOR were (are!) great games, but since then it's only got worse, not better (one would think that with all those new tools the writers would be able to tell better stories - but apparently it was the lack of tools that forced you to tell great stories in order to get the player hooked!)
greetings LAX
ps: I am still compiling a list of things that went either wrong or could have been done way better (or had been done better in the past or didn't need fixing) - If I do start another run (note: not finished with my current one, but I am frustrated ATM so I am taking a break - more so as the game nearly ruined my savegame (I lost 6 hours of playtime - luckily I had a backup at all...made that in case Origin might decide to delete the game because I was using a VPN to play early) I will play with a laptop next to my desktop (to note things I see that I don't like...will be long list I think ^^)