Eh, some of us are crazy enough to still want to mess with it.

As for design philosophy, I just really like the imagery of a frontline defender that projects a large visible rune on the ground around themselves and allies, keeping them all safe from harm. So, I took that idea and dropped it onto Runepriest.

As for is it a good enough defender, I would say it's effectively a 75% Defender / 25% Leader. You get all of the strictly required defender mechanics, and some of your powers that were already off-defendery are even better now, and the rest of your leader-focused powers are now there as nice bonuses instead of build defining options.

I've found this Rune Guard works very well in melee-heavy group comps where your allies are typically going to be sturdier than average anyway, meaning they can afford to take an extra un-mitigated attack, and then you can afford to spend a bit of your leader-y mechanics to sustain them.

I also find that the swap-Mechanic for Protection Rune and Destruction Rune allows you to play kind of like a Berserker if they could freely drop in and out of their defender aura and berserker frenzy, allowing you to either REALLY hunker down and keep allies safe, or go on the offensive and encourage allies to focus fire enemies.

It's been pretty fun, and I'm probably going to be playing on in a campaign that's starting up this Sunday, so hopefully I can get more data on it! I'm glad to see it getting some interest. I also have other homebrews in my signature link if you want to check them out as well!