I chose kits, because Variant Classes as per Unearthed Arcana was not a choice. I do recognize that many 2e kits suffered from bizarre mechanics (e.g., savage warrior acting as if under an alarm spell) and later power creep became an issue (e.g, the bladesinger). The former I blame on the underlying mechanics of 2e not being as streamlined as 3e while the latter I see paralleled in many PrC's (the only difference is that TSR used freelancers and WOTC uses in house designers).
However, 2e kits done right (e.g., the kits in the 2e "The Complete Thief's Handbook" and "The Complete Druid's Handbook" ) were really not much different than 3.X class variants (e.g., the fighter thug variant in the PHB and both the wilderness rogue and barbarian hunter from Unearthed Arcana). Like 3.X class variants they were a way to reflect concepts based on either cultural, environmental, or occupational specialities within a given a class. Furthermore, like variant classes in 3.x, tailoring classes through such kits were,imo, with rare exception, a better and more logical way of reflecting such differences opposed to take a feat, take cross class skills, and multiclass all just to qualify for a PrC (many of which aren't prestigious and are concepts that should be available to beginning players)