Based on the efficiency gains for both minting and redeeming by adding weETH to the basket plus the fact that ETH+ will no longer represent greater than 10% TVL for any collateral asset and a higher yield profile, I think this would be an excellent proposal for a basket change.
However, I say that with the caveat that the proposal to remove default protection passes once on chain: [RFC] Modelling how ETHplus would react to a deep and sustained stETH depeg and what actions we can take via governance to mitigate loss
The exit and liquidity complexity risk sticks out to me in particular with the stacked withdrawal queues that LRTs represent, risking the peg stability as you mentioned. Once the default protection parameter has been modified by Reserve and the proposal to modify it for ETH+ passes, I would say that this basket change proposal will be much more acceptable, at least in my opinion.