For example, how are we meant to gear followers when they need STR or INT gear and all that drops for us is DEX gear as a monk? It was bad enough before when we only needed a few slots but now we need a full set of gear that doesn't drop...
The followers also had there skills reworked, for example, the scoundrel now has ability that he puts a red cloud on the ground and anything in that cloud has a 100% chance to be crit for 3 seconds (depending on dex) so the more dex he has, the longer his abilities last/
So in Solo play, they are quite significant, and some of the emanated powers are actually useful, like the double shrine durations, which was useless to have before.
Even with the new follower powers the scaling doesn't make or break any solo push until the very top of the leaderboards. The abilities cap out at 25k main stat and followers get a 2.5 stat multiplier and 8 sockets you can dedicate to main stat. It takes like 7 "correct" non-ancient items to cap follower ability durations. An 8 gem follower with just their token is 33% of the way to their stat cap.
It's really not a big deal or even that impactful relative to the useful emanating effect either. The very best follower ability (Nights Veil) will see a 33% damage gain during the same 4s window when compared to a literally naked follower if you have 50% crit. More crit less gain. For a follower with just token + gems you should have a duration around 2.66s, gaining the other 1.33s of duration gets you a 22% damage bump in that window. On an ability only a small minority of players might be utilizing "correctly" with any consistency. And it has a 30s cooldown that can't be reduced by CDR gear.
Just slapping Occulus on a follower is an 85% DPS boost on its own. The abilities are pretty much inconsequential compared to just picking the right legendary gear.