In regards to crit pistol build. There are two unique pistols in the game that are actually quite good for that purpose. Both are .44, one (that is in possession of Wyatt in Depot A) is a revolver that has 32 base AP cost and 20% base crit chance, other one is from Upper Underrail and has 35 AP and 150% crit damage bonus and more damage. With both of them, seeker googles and occasional use of Focus Stim (my favorite drug, one of the reasons for which is that he is VERY easy to make and always sold by Heidi in Core City) it is easy to have crit chance for 60%+. With Rapid Fire and Point Shot you can make 4 attacks, most of them will crit.
With Paranoia and Gunslinger (and decent AGI), i was able to have first turn almost always, even when going in the area from which i run from combat earlier (you have penalty to initiative for that, from what i understand).
Also, after getting Ambush feat, i often employed a certain tactics in the dark part of the Underrail (i.e. most of them). Throw a flare directly under someone (it is important, does not work if it lands near target) and if you out of illumination of that flare, all of your attacks will crit, dealing quite a damage to target.
But after playing it for a while, i found too many issues with pistol build that made game quite hard. First, you don't have perception as high (10 max usually) as dedicated sharpshooters like snipers and AR users, which combined with a range of the pistol and penalty for special attacks made it a very lousy shot even with almost constantly enabled night vision googles. Second is a consequence of the first - i found myself very close to the enemies to often for my comfort. I savescummed with him more often than with most other chars. Third is that even if he is able to fire 4 shots per round, you can hit 2 targets at most due to how those special attacks works.
SMGs in theory should have same problems, but they do not, mainly due to how busrt attack works. With 3 target in the area of the burst you are almost guarantied to hit with decent amount of your shots even with ~10% accuracy. Maybe it should be nerfed a bit).
In conclusion, it is a very interesting build but not for the faint of heart or people new to the game since it requires good understanding of the game mechanics to pull it off. Killing Wyatt is a VERY difficult task without being high level or having Quick Tickering and patience + good luck. Using plasma and other special pistols on the other hand is much more easy and fun.
P.S. It seems to me that Point Shot and Gunslinger are working with Plasma Pistols in the current version of the game. Don't know if it is intended or just a bug.