This would turn the feature from “probably has to wait few days” to “no idea when this could get confirmed and nothing I can do about it because we don’t have RBF”.
@bitcoincashautist explained well above why IMO it should not be added back. In the long term, any such space will be filled up and free transactions will enter into a nearly double-blind auction similar to capped block fee auction, except based on coin age or whatever criteria are used. Predictable delay will become unpredictable delay AND in the long term it will reduce the overall ability to scale as it eats up a big chunk of block space. Alternatively, the free space increases with demand, further diminishing attractiveness to miners and reliability of the primary transaction space.
Thinking more about the long term steady state, if miners reach a state that orphan or other risks naturally put a soft cap on even unlimited block sizes, a fee market would emerge. That would drive ever-increasing demand for the free transaction space, making it behave even worse, and disincentivizing miners.
Regarding consolidation, in the long term everybody would benefit from that, so it’s easy to imagine that consolidation itself will be incentivized rather than generic free block space.
In any case, whoever thinks it is a good idea has a big task task ahead of creating a CHIP that convinces many people that it’s not only a good idea, but a great one with economic benefits heavily outweighing drawbacks. Not only in the current state, but considering long term impact on scalability and economics.