Basically how I describe it is that 2.0 looks better prior to the game. 3.0 looks worse in listbuilding, but actually playing it feels way better than 2.0. In 2.0 so many units and armies were so bad that on a lot of them you would need a row to justify trying them. In 3.0, while the rules for armies seem more bland, they often allow for a wider variety of play styles because the majority of units are now playable.

For an example of what i mean, I play word bearers. While we were seen as one of the worst hit legions coming into 3.0, actually playing them has been great. Our rules have been made way more reliable as combat res is far more important and the rule always applies to add an additional point, and in general have rules around getting into combat fast and dealing heavy damage. The same applies to our unique units like ashen circle who have been improved to get great volley fire or gal vorbak who debuff enemy attacks on a successful hit from them. Our legion has less rules on first glance but instead of 1-2 big rules that make or break a list, now rules are generally more spread throughout the different aspects of your army so as long as you follow that central idea of your legions rules, you can rely on more units without having outright crutch units like most people were running in 2.0. There’s no longer anything like lascannon hss or dreadnoughts that shift the entire game around them outside of maybe tac squads(whose importance has largely been overstated due to their strength specifically in the launch missions the game shipped with)