I agree with a few of the OP's points but not all that is for sure. IMO ME1 is a more enjoyable game for more playthroughs, while ME2 is fun the first and 2nd time around, but beyond that it becomes pretty boring.
The one thing I think that really makes ME1 stand out is the music. It's often driving, more action packed, while ME2's music is more subdued and less prominent. Espcially at the end of the game while on Virmire, Illos, and the Citadel. I feel a sense of urgency in the rythm and tempo. It seems like they borrowed some Star Wars sound effects, especially during shuttle landings. No suprise there afterall they are developing SW:TOR and just took some of tho
Another thing I find missing in the game is it doesn't feel like interacting with the universe but instead being wrapped up in soap operas about my squad-mates with their loyalty / recruitment missions. In ME1 the choices you can make on Feros and Noveria are numerous and very varied that add a ton of replay depth to the game. In ME2 the choices are pretty much binary the whole time. And those choices you do make relate to your squadmates most of the time since that seems to be the stories focus.
The lack of a speaking protagonist (beyond "This hurts you") hurts the fun factor for me as well. Having a villian I can attempt to reason with / know their motives and what's driving them on their plot really adds some good character interaction in ME1. ME2 villians are generic mindless entities that are there just for you to waste time reloading the thermal clips on your weapon.
The mako is missed by me mostly. Had they allowed a vehcile type exploration like ME1, but gave the planets a more realistic feel and left them wide open expanses to enjoy exploring I think that would have been perfect. Instead we get generic planet scanning and a lackluster vehicle combat. The one complaint about the mako was that some planets had very jagged edges / terrain that made driving on them not very fun at all.
Decrypting skill taken out wasn't much of a concern. But it did make squad selection for missions less important IMO. If you wanted to hack something you needed Garius, Tali or Kaiden, each with their own different roles they filled in combat. Now in ME2 you just bring around Miranda and your other favorite character and it doesn't make a whole lot of difference really. The lack of banter by squad mates on missions is also something very much missed that felt like the characters cared about the story. ME2 has little of this, because by and large you are spending more time worrying about your squard mates. I did feel like a theapist playing a paragon Shepard on many missions, which should have been Kelly's job.
The armor I am ok with, as there are some pieces you can mix and match. But a certain look of the armor may not have the stats you want. Instead of tieing the armor to the stats, allow the player to choose what stats he wants on a type of armor, and then allow him to choose the look. So when you discover a new armor type it unlocks that stat and armor look, but you can mix and match for greater customization / replayability.
I agree that weapon ammo shouldn't be class specific. It doesn't make a whole lot of sense, as firing a weapon should be pretty straight forward no matter what ammo you're using. Having the overkill / marksman / assisination type abilties removed was bad IMO. Instead these abilities should have been modified to the new ammo system so that you got 2 shots for every ammo when you activated the power.
The global cooldown when you use a power was sort of silly to me. Instead I thought each power should have a longer cooldown, and then a seperate global cooldown that is shorter. It makes using some powers that have long cooldowns very ineffective unless the situation explicitly demands it. Also on the PC version there are not enough quick slots for all of the powers and those of your squad mates. I wish they would have taken a week or two to give the UI a better treatment on the PC version. But instead we get essentially a copy and paste of the XBox version of the UI, which doesn't really work too well for me.
Well think that sums up much of what I wanted to say, not that I think Bioware will read / care about most of those points, which I'm sure have been brought up countless times on the forums. But what else are forums for other than silly rants and opinions