The ME1 menus was such a mess, that I wouldn't even say it was a good RPG.
It wasn't good, but that's hardly enough to stop it from being a good RPG.
It wasn't a good RPG, but that was down to the dialogue system, which only got worse in ME2.
Also, the gameplay depended on the Mako, which was mediocre in Story missions, and horrible in side missions.
I definitely disagree with that. Driving the Mako around was probably the only part of that game I found genuinely fun.
If I'd played ME1 first, I would not have finished it or bought ME2 and ME3.
I liked ME1 enough that I finished it thrice, and I did buy ME2, which I disliked enough that I didn't buy ME3.
I'm cool with straight turn-based RPG combat, but ME1 wasn't that good at that.
I still think ME1 has the best RPG combat I've ever seen within a shooter interface.
ME2's was made worse by the addition of thermal clips, the contrived level design (with convenient cover everywhere - I could predict when combat was about to happen based on the sudden appearance of waist-high barriers), and the loss of stat-driven aiming.
A legitimate criticism of ME2, is that mechanics of the game made biotic characters have significant disadvantages (I'd say useless, but high level players can make it work). ME3 was much better at making all three classes work equally.
With a squad-based game, class balance shouldn't really be necessary, except that ME2 made Shepard vastly more powerful than the squadmates (and worse, didn't document that).
I'm cool with a turn based option, but ME1's menu system was extremely flawed
I don't understand why you're talking about the menu (which was bad - but not vastly worse than KotOR's or DA2's).