Yes I played TW1, beat it several times, but it's been a while. I wondered if the sign selection was similar to to TW1 but I couldn't recall exactly, been too long. I don't seem to remember having nearly as many problems selecting & using the signs in TW1 though, but I don't recall how you selected or cast signs in TW1, I also used less signs in 1 than I try to use in 2 ( mostly due to combat difficulty ).
The truth is I also don't remember well but I think it was the same system. For TW1 fights at Hard I felt it somehow difficult in general and sometimes very difficult. But well I didn't develop much my character around signs so I end also not use them much finally. But I'm almost sure TW1 was relatively well design so you concentrate more on developing signs and use them more in fights, a player choice.
But I don't believe just because TW1 had one similar UI mechanic that the rest of my points are invalid. It's also a fairly rare mechanic for PC only titles.
And it's fairly ancillary to the point but they did try to release TW1 for consoles but the 3rd party porter they hired mucked up the job too badly to bother.
I don't disagree fully on your analyze but I think you want proves it so much that you forget use a larger point of view and can't see some other good reasons than console could have lead to some of those design points.
About the signs working with a selection key and an action key:
Even on PC many players don't like have to use ton of shortcut keys during action. TW1 had already its load of shortcuts, 3 fight modes, 3 custom shortcuts, 4 movement keys, jump key. Add to that 5 weapons keys and 5 or 6 sign keys, and they consider it too much and I agree. So instead they choose design an action game with pause, allowing less action keys and use pause for some selection, selection for fight mode, selection for weapon, selection for sign and just 2 actions keys for all of that, attack and cast sign.
About the lack of shortcuts bar:
I think you don't realize the obsession of modern games about immersion, hence a large bar of shortcuts is considered as immersion breaking.
Also your comparison with a game like NWN2 is totally wrong because it's a non action game and a mouse game, both justifying totally the bars of shortcuts. An action game with no mouse point and click controls during action makes this choice doubtful.
About auto targeting:
I haven't played the game yet, but I think I know where it goes, on a fight system designed for an acquired target. If you remove auto targeting you will most certainly get a strange system I experimented a little in another game. In that system you need first acquire a target then can start fight, it's rather awful for fighting groups. TW2 had the requirement for fighting groups, there's a good chance it's the true reason of the auto targeting (group fights and a system requiring to acquire a target).
For the mouse wheel:
I always wondered why I had always commands linked to that crap, perhaps they also estimated it's not good as a default? And the problem is larger, it's the customization of controls is quite limited. TW1 had a similar flaws, more than console influence, it's more probably an underestimation of custom controls by the team.
So this let the inventory and menus managements, for sure consoles are the reason behind that points. Other than that, I'm not sure at all you are right for the other points.