I like the Rock Gronch a lot. It helps me win a lot of games, always targets the treasure gnome (?) and other pesky enemies and has good stats. In fact, I think the Rock Gronch is so strong it disrupts the game balance. It just dwarfs everything else and decides 60%+ or my arena games. There is no reason to use any other green creature, ever (I think Grimchop is sometimes a viable alternative). I regularly have/see RGs with a power of 20+, sometimes 40+ (in bounty games). In the arena, the first player to get an RG to grow past 15 gets an almost guaranteed win, there is just nothing to stop them. Stunning them only helps them grow more.
It seems that most Arena players use the RG (some other creatures like the Elfling also seem to be somewhat OP, but not as much).
I hope the dev team keeps a close look on the balance and recognizes this issue. I would propose to change the Boulder Hurl level 4 bonus to +2 strength instead of +AP to strength. RG would still be very strong even then.
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