tldr: not voting on your own proposal eliminates nothing and puts you in a unfavourable/unfair position(you need one extra vote to offset your abstain) and actually promotes under the table deals, so i think council should be able to vote on their own proposals and then take the responsibility for it.
rationale:
How do you prevent council member A to “push forward” proposal from council member B, and B doing the same in return bsaically bypassing it. Both of them being xgov whales. You know basically what we’ve seen in the past with “we didn’t vote for our own proposal… but our buddy did and we returned the favour ~whale”? This is even more so, as you will need a whale backing to get you voted in the council since it’s proposed to be voted as part of general gov… 
I feel that the “not voting on your own proposals” is actually accelerating a potentially corrupt voting body instead of preventing it. Because the council memebr proposing as xgov, not being able to vote on their own proposal requires them to get one extra vote (favour?) in comparison to non council member.
Hopefully tere will be some redundancy of skill-sets within council, but if there isn’t, abstaining from voting might axtualy be harmfull to objectivity of the evaluation: Let’s say you are the sole person on council able to determine the “proposals” implementation of the Smart contracts…if you abstain, the proposal fails to get fairly measured for this aspect.
I do agree council members should be able to participate and propose stuff in xgov.