I'm not a hardcore veteran but I do remember playing in the first MechWarrior on a 286DX Turbo rocking EGA video.
I have watched so many 'let play' on YouTube I've decided just to wait awhile myself until a few more patches come out that fix the enemy spawning and AI.
but this is just my two cents
The spawning has already hit the first round of fixes, quick patch-overs to make it less blatantly obvious they are spawning behind you. The next fix is supposed to be a bigger one but requires testing before implementation. The higher-level campaign gameplay, being a merc and getting paid to slay, is pretty solid though. When the in-mission gameplay is good, it is right up there with the previous incarnations. MW5 doesn't really have a huge delete button for mechs, at least early in the game, so fights are usually fairly meaty and reasonably drawn out.
I have to say that now that I have realized the weapons are simple tiers that the stripped-down mechlab really blasts my ass. The impression I had from AMAs was that the weapons were going to have tradeoffs between manufacturers, not just be an exercise in looking for more bars. HBS Battletech, despite their simplified + improvements at least retained the idea of opportunity costs (even if some were clearly superior to others, like the Kali Yama AC/20s vs. any other maker) so there were tradeoffs to be made in mounting one or another. That's hopefully the first thing the modders tackle; not just different tiers, but different advantages, like longer-burning but cooler-running large lasers or PPCs with a higher minimum in exchange for more damage. They already half-way did it with stream LRMs and burst-fire autocannons, so might as well go whole-hog. As of right now, it is a straitjacket.
As for nostalgic comparisons, MW2 was still an amazing game even though tactically the AI mechs only closed to short-range and started circling. They had no other tactics whatsoever, which was only disguised by the fact that in early missions your mech was (probably) so fast that you could force them between circling and pursuing with a single hard turn at high-throttle and in later missions by your weapons being able to delete hostile mechs at long range. I still remember (or rather, I cheated and reminded myself with a playthrough) of fingernail scraping the fire button with Ultra Autocannons because they'd fire like 10 rounds a second at TT-accurate damage values vs. TT-accurage armor values. Instant mech death.