I had a similar idea! I was thinking that you could also get a temporary shield and/or health regen boost and/or mana regen boost. Your health, mana, and cooldowns are otherwise unchanged after you switch. Every time you switch sides, your chance of switching again in the same game decreases significantly. This would hopefully deter people from trying to sabotage the team they got switched to in the hopes that they'll switch back to their original team.
I was thinking that it would be okay on the typical SR map. I definitely don't know enough to understand why the map should be smaller, so I think that the SR map should be unchanged.
Every [time interval] some players swap teams and location. For example, if red and mid lane 
switched with blue and bot lane 
, you would end up with red and mid lane and blue and bot lane . There would be no spawn area required, besides base.
I don't know how how this game mode would work into the way League works though. I definitely wouldn't want to wait on the loading screen to switch. Hopefully, it wouldn't happen that way.
I'm really unsure how to handle the potential problem of someone sabotaging the team they got switched to. I suppose that you could make it so that there is a possibility of no players switching at all after [time interval].
EDIT: I had to rewrite most of this because I used a "less than" sign, I think. The message from the "less than" symbol to the end of the message disappeared completely when I posted. As the professionals say, "rito plz fixx"
