Wow. That's one heck of a blocker. A huge improvement on Stoic Ephemera for only more. I know I'd swap Sunweb out of all my decks if this existed.

Mmm. High power on walls is less expensive than on attacking creatures; but still not quite this cheap. Wall of Swords is still a darn good wall. This having first strike is just.. wow.

Well, considering Sunweb costs less (more of its cost is colorless) and the fact that it has 2 more toughness (as in, assuming attackers all have equal power and toughness, they can both block 5/5s and kill them, but not block 6/6s), that makes this really well balanced, except it needs a bit less toughness. Remember that having less toughness makes it more vulnerable to targeted damage.

Yes; but "Has a weakness to some red decks" isn't a very strong justification for reducing the cost.

Not many other walls are "I cannot attack except with creatures of toughness 6 or more, and first strikers" This is very very strong.

It's been a while since the cards we're talking about saw printing. Truth is, we don't see many creatures with defender nowadays, so it's hard to compare this to modern cards. This looks fair to me, though, considering modern power creep. White can do this flavor-wise, uncommon can produce box stats, Defender trades in for First Strike and Reach. A bit much, but doable.

First strike makes this a lot stronger than you're giving it credit for, elvenchakra. The fact that this can block little creatures, which Sunweb can't, is also a big difference.