Ok before you instantly think ok polls, been asked before.
Well don't because this is a suggestion for the battle subway which would work like this.
Ok so when making an RMT we would have an option to add a poll which may be something like the following- 'Which of my team should be replaced with a spinner?' Or 'Would my team benefit a spinner'
Obviously you can choose the poll and answers but the results of the poll are classified to who votes.
This would help the team maker.
I think smogon has a similar system.
Anyway just a suggestion.