I’m considering softening it a bit by allowing the shield to stay active as long as enemies are near OR the gladiator has combo

That is a pretty solid idea, it would definitely make it feel more worthwhile to save your combo up between encounters. It can be a difficult resource to manage effectively given the other extenuating circumstances like environmental hazards and "oops all melee whiffs, womp womp" so feeling less pressure to just spend it at the end of every encounter would take a load off!

The shield persisting through the Combo would be a great addition, it would definitely feel better. I'm looking forward to that.

I'm wondering though

The fact that we can't begin stacking Lethal defense until the passive shield triggers. Is it intended? Would it be too strong if the passive had full uptime on top of the Gladiator talent?

Personally, I don't see it as clashing. The gladiator is the more active sub-class and currently, in the situation where you're about to kill an enemy but your shield is up, strategically, you should not end the combo and be in search for your next fight. Your shield will be in cooldown but you have combo built up ready for a finish and reset. The gladiator should be played differently than the berserker.

But the change you proposed shouldn't be game-breaking and it'll make some players happy so I'm not opposed to it or anything. It's probably a good change.

It seems if this specific change was intended as a buff, it may be a bit of a nerf. Now, when you have just a few points of shielding after a fight, you hold a meagre shield rather than going into reset right away. On the other hand, if you had most of your shielding in tact, that means the fight was ideal and minimal damage was sustained. And you would get a reduced immediate cooldown previously. It just seems like the worser case scenario got worse and the better one got rewarded.

Just thought I'd provide some feedback and I'm not looking for any change or reversal. It was manageable before and I'll manage with the current mechanics.

It's deceptive though, right - Old Gladiator would persist the shield through the next encounter regardless of their life total whereas Gladiator even on -100% cooldown will still lose the shield at end of combat, and if you're storing combo for the next encounter it means you're not resetting your cooldown.

I think combo is a frustrating currency to manage because it can go sideways for a lot of reasons. Maybe you miss too much, maybe an opponent doesn't die to your melee damage but some other effect (blazing enchant, thorns glyph, toxic/corrosive gas, enemy "friendly fire", any number of things) and so you don't get extended turns to re-engage in melee so the timer runs out, etc. Maybe if combo were less goofy to manage this change wouldn't feel quite as much of a downgrade for Gladiator, idk.

But now there's an added pressure to keep your shield cooldown as low as possible, which means you're actually killing with combo hits consistently, so you're trying to hit this sweet spot between doing enough melee hits to build combo but not enough to accidentally kill with regular attacks, but getting enough successive combo to kill with your chosen move. And you have to be <=50% health or the shield isn't even in play. So it's the combination of shielding requiring continual cooldown resets, being on low health, and managing an awkward resource in Combo hits to keep Gladiator, uh, gladiating

It feels like a big change from the old Gladiator, where the shield was already actively managed rather than passively; you could always choose to combo kill and refresh the shield, cooldown not even being a thing. Combo was still awkward but at least you could accrue it at your leisure and spend it when you saw fit to gain all your shielding back at once.

I will continue to try and refine my approach to Gladiator since it just doesn't function as it used to, this is all still pretty early analysis on my part. I don't assume everyone plays the game like I do, there are a few variants of Gladiator given the way combo hits get their damage, and maybe a different one that's more aggressive and less of a wall of EHP is simply more appropriate now. But my old standard method, where there was less pressure to sustain and use combo and shielding was always present and ready to be refreshed is definitely not in the game anymore.

It feels like you’re constantly fighting against your own defensive mechanics, rather than having them synergize.

This is a great way to put it. There's a lot of tension between Gladiator's mechanics right now, I don't feel like they're pulling in the same direction.