I hope you won't mind a Ground Ops comment.
If the two are not separated and something comes down wheels up or breaks up, you are likely to find re-declared distances on what - if anything remains operational.
Had experience of two wheels up on an intersecting runway, albeit one short and another past the intersection. If weather had necessitated CAT III, you would have all been diverting. (obstacles only just outside 90m).
Again, if something breaks up, you may well end up with debris in the alternate runway's clear & graded area or obstacles in the LSA. Not helpful if your calcs have not allowed for Murphy's to rear itself!