Hmm, I'm still level 60, and although battles are slow, I've been able to last a little while with Earth, Water, Air/fire/light.
I like to go on the defensive, to last as long as possible, so I have all three prof points in health for my tank, who is at 15,000ish health.
You're very correct, the battle style of the lost grove is so vastly different from everything else, that even with my 15k health tank, my battle party doesn't last very long, and all of my defeats on my tank are from the lost grove.

See, that's the clincher right there. I realize the tank gets attacked the most but even with high agility and high health, it still gets knocked out.

What irks me is that my healer, which was useful until the grove, is now a liability and doesn't do a thing.
So perhaps I need to abandon the idea of the traditional party make-up and instead of a tank perhaps have a party that is largely on the offense.

See, the tank is nice but if all it does is act like a sponge and is basically ineffective in battle then it bogs down the rest.
So on one party I have a battler, fire bender and a tank with reasonable attack. It works...marginally so I may abandon the tank idea and have a heavy hitting army to take down the beasts in the grove.

I guess a change in tactics is what is needed.

Edit:
Ok. The heavy hitter tactic did not exactly work out the way I anticipated. Even with very strong creatures, they did not do much better.
So maybe I will still use a tank but instead of relying on allocating points for health, I use points for agility and intelligence. At least for shadow tanks. I don't think shadows need dexterity for their attacks but having a magic user that actually does something for the whole team helps.

See, if I have two battle pets that are at levels 62 and 61 and one fire magic user at 60 then I should be able to breeze through places like Astryls Tranquility. Technically I should also have less issues in the grove.

Have to keep trying. As soon as my essence enhanced Ny'venne gets to adolescence then I am going to start training it. Same with a new magic user too (which is also essence enhanced)

Just jumping in on your messages! ^^

I also find battling in the zone to be slow, at least slower than many of the others. A lot has to do with how slowly I move around the zone.

The fastest way for me to level up has been the Dungeon of the Forsaken. One round of that boosted my pets a whole level...

Also, I used tanks with all agi, or 2 agi/ 1 int/str. Not many people seem to like this, but it works for me. I found my tanks got hit too much when boosting health, and the high health didn't help them. Maybe worth a try?

I'm now lvl 65, and can say that things got much lot easier after lvl 63. Then they got a whole lot easier for each piece of vinethorn equipment I added.

Right now, with vinethorn and lvl 65 I switched from shadow/light/air to water/air/air. I like faster, more attacking teams. But I just couldn't do it when I first got into the lost grove, and a balanced team with light worked best for me.

You know, this is what happened to me when I tried beating that Veirna character in the Dungeon of the Forsaken.

My tank was level 60 with high health and somewhat reasonable agility but I got pummeled. Shadow works ok as a tank but like you said I am toying with the idea of using water as a tank or having a water and air fighter but I am trying to get my pets to level 63 but it is hard because there are not too many places to do that once your pets get to a certain level so I am just going to have to grind in places like the forsaken dungeon, Astryl's Tranquility and the Orchard.

But..I can still hold out for a few of grove battles now. :)