There was/is a thread in requests pretty much similar, that was more geared to enabling a player to reclaim an aircraft out on lease to another player who was neglecting maintenance and thus damaging the aircraft.
I'd foresee some issues with this idea : recalling the aircraft would leave the current user in the mire, perhaps even unable to replace it quickly enough with consequent damage to their airline, particularily if they then lose expensive/rare slots as well. As they have leased the aircraft in good faith, that would be a bit unethical, in my view. Forced recall of an aircraft which the user is not maintaining is another matter, as they are the 'unethical' party in that case, so that seems a reasonable option to me. But how the game could differentiate between the two cases is another matter.
You can always limit the term of lease and thus have a pretty good idea of when the aircraft will be returned : that does make it harder to 'sell', as some players want them for a longer period, or to be able to extend the lease if reqd for their own plans.
I was looking over the published accounts of a small-sized feeder airline based in the States, running mainly leased Embraers : one item was interesting, as it seemed to be a sort of 'sinking fund' for maintenance checks, paid to the lease company, as part of the lease deal. It seemed that when the airline ran a check, it could then reclaim the cost from the leaseco, which held the fund. Not strictly relevant to your point, but shows how 'real world' lease deals can get a bit complex and thus hard to model into the more simplified 'one-size fits alls' approach necessary here. I'm sure I recall similar terms in lease-deals for companies I have worked for, requiring certain levels of maintenance, insurance, user-training, etc, failure of which could mean the equipment being reclaimed. I dont recall any which allowed the leaseco to reclaim just because they had another use for it elsewhere.