That maybe the case but in many peoples mind including a great number of the hardcore crowd Halo 2 was the best playing of the series. A halo 2 clone without any of the glitches and in HD is for many an ideal halo. Ideally thats how id like halo 4 to be, Sure add some form of equipment to it but keep the things from H2 that people loved like the jump hight, movement speed and kill times.
Even discounting the glitches there were a good number of things just broken with Halo 2. Off the top of my head:
- SMG only starts
- Energy Sword's infinite ammo/no cooldown thrust
- PP/BR combo's effectiveness
- Auto Aim for sniper/BR
Now sure, you can adjust these things but now we are getting a little bit revisionist about things. What Halo 4 should (and ultimately will) be is a conglomeration of previous ideas in there series that worked well, omitted ideas that didn't work well, and some brand new ideas to move the series forward.
That's how every Halo game has been up until now. Stuff will make it in from CE, 2, 3 and Reach. Stuff from those games will also be left by the wayside. Saying it should be HD Halo 2 without glitches is myopic to say the least.
The good news though is I think you will definitely get your much wanted HD Halo 2 remake/port at some point. I know I would love it despite 2 being my least favorite MP in the series.