if mining pools would simply just accept transactions into blocks instead of ignoring them all the time, there would be no issues.
The amount of tx's that can go in a block is limited right now (well its by MB but thats essentially the same). Additionally full blocks DO take noticeably longer to propagate the network and do increase the risk of the block orphaning. Some miners take the risk and include free tx's for altruistic reasons, but most miners are running a business and they are not going to risk their 25BTC reward for free.
seriously.. your going to roll with that sheeple excuse passed down from a miner trying to hide their greed.
blocks are NOT 100% full, there is plenty of space in all blocks to accept all transactions that appear in the period between each block. no one should be waiting more than 30 minutes to have a tx accepted. and on the very smallest of occasions, a few people may have to wait 20 minutes. (very few occasions)
secondly the reward is the reward. end of. they should not be compensated for ignoring transactions. the reward should be for allowing transactions(the whole point of making blocks(infact the whole point of what a blockchain/bitcoin is)). saying that miners should get a bonus for preventing the loss of a reward.... that is the weak and pathetic excuse miners give.
no one should get a bonus for only doing half their job.
again bitcoin is a ledger system, the point of the ledger is to have details of transactions in them. if miners want to have a blockchain of no transactions per block because they are in the belief that blocks should be empty to get paid. and that entering a transaction should be a 'premium' then they need to seriously realise that they are not part of the community and simply greedy selfish people that dont care about bitcoins usefulness, and only care about their own wealth.