Would it be a bad idea to give Swain a max mana scaling on his ult?

Swain is super strong. If they add any more power, they'll break him.

Riot shouldn't touch Swain til they rework him. buff his damage and they'll likely lower his healing or nerf his snare duration/delay

Swain doesn't need buffs. He is underrated and extremely powerful in the right hands, moreso than most champions, he doesn't need anything more than some QOL tweaks.

He is underplayed because his actual gameplay is boring as hell. It boils down to:

1. Survive until level 6 and hope no one on the other team is smart enough to rush
2. Pray to god your lane opponent is some potato who has no idea what Swain's kit does and lets you get fed off them so you can actually make your own big plays. Otherwise:
3. Press R and walk into the middle of the enemy team
4. Activate when you are low on HP, and twiddle your thumbs for the duration while you 0-100 heal off everything around you and no one can do anything about it
5. Rinse and repeat until your teammates finish off your enemies for you because anyone dumb enough to stand next to an ulted Swain for that long in the first place would have lost regardless of what champion you picked

He is very strong, partly because of his kit in general, and partly because many people don't know what he does in the first place and do stupid things while fighting him. But the fact that his kit relies mainly on him just getting into the middle of the team and standing there outhealing everything just by existing makes him really boring to play in general. The main point of mastery in his kit is actually his mana costs and his cs'ing, both of which are dreadfully painful to perfect. His last-hitting is horrible yet it is tied directly to his mana returns on his passive, and his mana-hungry nature just isn't fun to deal . Perfecting mana management on him isn't really a skill you can show off in the way you can show off your Q management on Nasus by getting 500 stacks at 20 minutes, or your Ferocity management on Rengar by instantly chaining together multiple skills and getting the right empowered one off in the blink of an eye. Overall he's just boring to play despite being strong and is further discouraged from widespread play by dated visuals and awkward mana costs along with a clunky "feel" to his kit. Kind of like .

Oh you want a new ryze but with both mana and health regen steriod?

For this to be a thing you'd have to nerf his ratios and or bases elsewhere because he is already strong. That would only serve to lock his build path. You don't want that.

I don't feel his ultimate is his issue.

Swain's kit has a ton of problems which keeps him from being a strong pick.

Mana reliant. DoT Mage. Weak wave clear.

Two single target spells, and two AoE spells so his 1v1 burst isn't fantastic without hitting everything, and his team fight isn't fantastic either. No stuns or strong engage tools either, only a delayed AoE root.

Swain's trying to be good at everything, but really isn't. He needs to max his E to get the most out of his damage, but needs his W to wave clear, but also needs it to force people to fight him, all while being forced into a build with tons of mana and screaming for blue buff.