[Razorback]

Heartless thats a good proposal, infact flawless apart from the exact numbers of when what is the case.
The situation you describe is easily exploidable, the #2 would encourage ppl to gang up on the #1 and then after getting themself on the #1 spot go randomly for easy roids while its partners keep the former #1 busy. This would lead most likely to a prolonged phase of a block while the new #1 can work on its advantage for the time once the former #1 drops out of the top 5 .
On a 2nd thought the "first" #1 of the round would have a major disadvantage, aslong as they fight back the new #1 can gain on the rest without fearing a block, unless the first and former #1 drops out of the top5 which can actually take some time (seen in r10 fang).
Also there would be the need of a limitation of how big the block is allowed to be, the block would otherwise not disband but just kick the highest ranked member each time. This would be bad for the game mechanics, as it would not encourage the alliances to try hard because they only can exspect to be smacked to pieces by the rest of the now blocked universe. i.e. dedication to the game would be an unneccesary gift and winning only the random result of the last few ticks ( can #1 hold its position over the last hours or will it be replaced by the #2 which is in the block right before ticks stop, unfair imo)