I don't play lifesteal but I'm going to -1 this suggestion..
Reason: The whole point of a KoTH is to be the best team right? Invis potions are part of the game, and available to all players. Having a permanent glow effect to the players who have KoTH capped gives them a disadvantage to other players.
For Example: Let's say you're invis and attacking KoTH because they have a glowing effect. They can't see you while your invis, but you can see them while their invis.
I really suggest you experiencing a koth in opls before commenting. Koth works completely different as expected in opls. Normally players gear up, create a team and cap koth together. Logically if you have a team with likely same player count you'd stood a chance, which isn't the case for opls. In opls's koth there are around 25+ players EACH koth gathering in a 5x5 block area. Everyone using invisibility to prevent his name. The issue is if only 5 people are in a team and have luck capping koth, you have zero chance getting that koth no matter of how many people are targetting them. The reason is simple. You cannot clearly see who is who if there are literally 25+ people. The worst case scenario is that 5 people tank up, use invisibility as their advantage, swift sneak III and just sneak around so other player get hit, permanently healing their armor since the new update allows you to buy experience bottles mid combat.
This scenario happened very often, it not only a one time case, no. Everyone is abusing this strategy. This just ruins the gameplay. Since of that it would help way much better if the glowing team would recieve a permanent glowing effect until they leave the koth. This would benefit all other player trying to claim the koth, and it would be way much exciting for everyone.
As I said, please checkout atleast one koth to see how boring it is before giving a reply / statement.
Koth isn't there just to sneak down and tank completely up.