Having ample accuracy is one of main reasons i proposed Perception 10 and maxing Guns skill at every level. This alone quickly buffs up accuracy to max in Normal mode, where enemies' Evasion is not scaled up nearly as much as it happens in harder difficulties. There's also Night Vision goggles possible to find from loot starting in Depot A, on top of that.
Trying to fight at long range even early in the game - is useful, due to early game enemies having limited (often, none) ranged attacks, and when they do - their range is limited, like dogs' spit and burrowers' ranged attack. Further, early game enemies don't have huge mobility (except burrower spawns, which are very low damage melee attackers), making it possible to effectively kite them. It's a YMMV / playstyle thing i think - some prefer the safety of long range, some prefer higher early game hit chances pistols can indeed provide, especially for lower perception builds.
Low-AP shots for pistols available early game - automatically means low damage, as it's lower caliber non-Hammerer pistols. Low-AP if to compare to assault rifle single shot mode, that is.
Very true about sniper rifles, these need core feats taken to really shine. However, Aimed Shot + Snipe + Shooting Spree are not late game feats - one can very well get all three before even stepping into Depot A. If not, most likely 3rd one will be taken during or very soon after Depot A. Enemies after Depot A become lots more tough, and sniping rifles give a big edge then. Personally, i always felt Depot A and everything before it - is a kind of tutorial part of the game, and the real game - is everything after it, btw. Can't rule out sniper rifles for a Guns build, me thinks. They are good for most of the game.
One other thing which always make me hesitate to recommend pistol builds for anything close to the base stat distribution i suggested above - is low Dex. Any great pistol build must go high Dex, and careful distribution of stats elsewhere. I even dare say, any good pistol build - must be 3 Perception and Versatility, just because it saves so many stat points while going for real high Dex. But that's not a beginner-friendly type of a build...
Last but definitely not least - it's not "either-or" for Pistols and everything else. Like you yourself mentioned, SMGs can complement pistols well - but so can any other gun type. Pistol + sniper rifle is a classic combo, as is pistol and assault rifle. Can also switch setups for specific fights - mix in grenade launcher here and there, for example.