The center flag needs a nerfbat, and fairly badly. When you're early on, it's not too bad. The extra creeps are just cannon fodder, and can be easily AoEd with (insert skill here). While your opps are taking it, you can get that much XP owning creeps.
However, at the later levels, it's ridiculous. At Priests when the creeps become significant, e.g. DOUBLE as many Giants, 50% extra Catas and Priests. I applaud your effort to scale the flag up, but you've gone way, waaay too far with the +1 of every type that currently spawns. When you hold the flag, all their creeps (with associated XP and gold, too) are belong to you, and thanks to Catas, their base and Demigod too. For me, this would create interesting gameplay, IF you were not required to break through previously covered overpowering odds to recap the flag.
Something better would be, say, +10% HP for every creep on the map. When it comes to 200 Minotaur HP or 220, vs a 200 damage AoE (looking at Torchbearer) that's a significant difference, but hardly overpowering.
