In D:OS1 the number of talents never increased either, you saw what was available from start. Why should it be now different?
There were a lot more options for specific builds with DOS1's talents. Things like Bully, etc, which were specific (viable) talents for specific builds, were abundant. Overall, DOS1 had more talents, anyway.
Now, once you hit the point where you've got 3 - 5 talents to choose from, basically every melee takes the exact same talents. Most ranged builds end up doing similar things. Additionally, there also aren't any of the high requirement talents like in DOS1 (ie. ones that require you have 5 in a specific skill) - and while those high requirement talents weren't all that great, they still encouraged you to make unique builds and work towards them, so the placebo effect of it made you feel like you were doing something different.
Heck, even after the EA, there were more talents removed than talents added. Backstab was removed as a buff to Rogues (to help with the nerfs they received). Same goes for Zombie, which was basically just turned into a race on its own. While there might have been strong reasons behind the removal of those talents, it still removed options, and thus limited builds.
In exchange, we got Ambidextrous, which is honestly an awful talent, because it relies solely on having damaging consumables to make an objectively awful build even remotely work, and damaging consumables are generally just weaker versions of spells available at the same level.
I'm hoping for a content update in the nearby future just to help diversify builds a bit - but, even if there isn't one, I fully expect be a number of additional options to be added with the inevitable Extended Edition. Honestly, I would have gladly replaced one of the early Kickstart milestones with, say, tripling the number of talents available and adding a lot of niche ones. Talents seem like the most important part of diversifying any build, but right now we've practically taken three steps back since DOS1, despite the fact that talents come down to pure numbers 95% of the time, rather than actually creating new assets -
so it should be easy to mass produce decent, niche talents with minimal effort.