It's interesting to see the differing opinions on this. Some people hate runes. Others (like me) would have left the game a long time ago if it weren't for runes.
In my opinion, this game is boring without them. There's virtually no strategy at all. Take away runes, and this becomes a mindless clicker game. Now mindless clickers are fun, but I need something with deeper strategy to keep me engaged for months or years.
For those who complain about not having enough offerings, just wait. I think I have around 10,000 unused offerings sitting around. Buy offerings every day in every shop, and occasionally use the double drop items you get from contests, along with tons of stamina, to farm equipment. You'll eventually have more offerings than you know what to do with. You'll also have more runecite than you know what to do with. I have 3.5 million!
Yes it is. Sure, if you happen to have exactly 30 more dodge than your enemy's accuracy, you have an advantage, but that almost never happens, and it's a tiny advantage anyway. Hail will give you a very small extra chance of hitting, while Tree will give you +15% health, which for some heroes at C+4 is more than 100,000. Hail is never the right choice, for any hero.