nuh uh.. life steal! Trust me, the assassains will fair fine. Can you remember any multiplayer games, where your entire team was assassins? I can remember many of those, and we did fine. It lies in skill, not monks.
So that would be: monks + skill >> skill > monks. Though i dont play aggressive enough to the most benifit out of all Assassins i have never felt like i was going fine with a full team of them.
Not having monks means that you have no regen so you have to go back to crystal or waste large ammounts of cash to get health back. Minion builds are going to slaughter the week assassins and the rest will still have trouble playing against them.
Its not just the monks 2 out of 3 of the top demigods are generals and UB builds gernally factor in a bishop to beet LE/Oak(/Sedna) rook will die because minnions are now vaible. There are probably a few more bs strateries that generals can no do since no general is there to conter them.
Hopefully Epoch 4 is only 6 weeks away (or just to the end of the tourniment) or ballance attempts are made by GPG.