Well, they have oorah (super cool), build sandbags, have molotovs, have at nade, have the possibility to upgrade to 7 man squads, they also are 6 man and can crew abandoned weapons more easily plus merge with other squads (such as, for example, engineers making their flame ugrade almost nonretreatable) - all this is non doctrine (that's more abilities compared to grens)
With doctrines they can get ptrs, more powerful at nades with the cloak ability to surprise vehicles; they can repair vehicles (super powerful when you have 3+ vehilcles), they get ppsh and the ability to hit the dirt. All very useful and probably I've forgotten about some abilities. In my opinion, all those utilities add up and may win you the game if used right. Grens, contrary to what is written in their game decription, have fewer abilities than cons and are easier to wipe. It makes perfect sense to finally do sth abut it - I'd add more abilities to grens rather than buff g43s, for example.
They also can't do anything on their own without doctrinal dedication or massive fuel investments, most significant one being gated very late contrary to all other infantries.
Do you want grens to have more abilities at the cost of being impotent in combat unless you pick specific doctrine or are at mid/late game?