Suppose a large pool finds a block with very little or no bonus reward, the pool can old this block and try
to find another with better bonus - block.
when the pool operator will see another block announced, he could try to announce his "bad" block hoping
for it to catch the other block.
Now, there might be more than one smart-ass like this, so each time 3-4 blocks will be announced together
forking the blockchain.
There are no transcations without a roll bonus, so it is better (statistically) to announce solved block immediately

You probably right!
That's why I referred to the issue as minor, theoretical one.
Furthermore, by the time the pool is trying to solve a new block for the same transactions
he can announce the block and find a new one...
In spite of this, this (very) little hole is still there... and it's bugging me
