I just want to toss this in: I think the Hakkapeliita Great General stacking promotion would be a bad idea for two reasons. For one, it only gives +15%, which won't even actually be 15% boost after everything else is factored, and then only for one or maybe two units, probably at the center of the line, probably facing other infantry. With cavalry, that can work, since they can and will go after vulnerable targets where thay can really actually make a difference even on just one unit, but the more important part is this: Hakkapeliita could move after attacking. This is huge. Because Hakkapeliita could keep out of harm's way. Caroleans cannot. They are in fact meant to take the brunt of any assault, although they are not the greates at it with March's defense penalty. It is very dangerous to put your great general on a Carolean.
Maybe I'm overestimating the likelihood of the enemy focusing down the unit your Great General is on, or underestimating their mobility and ability to get away after a battle (particularly on the attack), but it seems like it placed them in a lot of danger. I could very well be wrong, but it seems like it would be much easier to be caught out if you're incentivized to put your GG in danger like that. Maybe that's good thing to represent them riding among the troops, but...I'm not sure either way anymore. Maybe give them Great Generals I promotion as well? That might be too strong with Sweden's ability, but...I'm not sure at this point. Healing on victory is probably a bit too powerful now that I realize what people meant about Swedish cannons, but I think Charge wouldn't be too bad.