Remember that now Grenadiers can get City Raider promotions now. However, being Melee also means they wont be able to use Pinch
. A 10% City Bonus and/or +25-50% attack bonus vs. Muskets would probably help.
I just think of them as a renaissance maceman, good at offense, but still vulnerable to horses, and not meant to stand up to infantry at all.
Cannons also get CR, have the same str, and have those important bombard/collateral abilities. Also, choosing between MSci and Steel is a direct choice in 99% of games...you can tech either first.
CR melee, even at str 12, won't keep up with cannons. And if you're leading with cannons, you do not need CR troops but rather stack defense + garrison forces. Melee grenadiers do not fill that role well. In fact, being unable to upgrade to CG Machine Guns is actually a detriment of the change.
I often wind up skipping Msci because of this problem. Grenadiers don't serve the stack D role especially well (the only thing cannons are actually vulnerable to, cavalry/cuirassers, beats grenadiers), and are far less effective offensively than cannons. Considering that steel also unlocks IW, is on the path to combustion, and allows artillery to be researched, going msci instead of it (or at all in a lot of games) is a tough sell.
Anyway, with the change to grenadiers, it might make them weaker in utility now that I think about it. Pikes actually serve the anti-mounted similarly, and now you can't even get CG. They could be ok for general-purpose defense but vs non-mounted muskets serve that role just fine and are cheaper (with terrain advantages, including guerrilla which gunpowder can take but not melee, muskets could actually be better stack defenders outright).
Grenadiers were a little better in vanilla but now are almost entirely a niche troop. At tech parity you could use a couple of them as city busters against tough rifle garrisons that have been softened by minimal collateral, but that's about it. Other than that melee grenadiers are no more impressive than gunpowder. In fact, I'd mostly prefer the gunpowder variety on the rare occasions I'd use them.
