If Trump has 50%+1 then he's golden. If his voters are not the majority, then they need to come to terms with that.
The point of a party is to come together on a candidate who is acceptable to the majority.
If we allow a plurality to be the victor, then the behavior of everything changes. You will see more and more candidates sticking it out to try to keep others from having a plurality. Division will increase instead of the system working towards a union.
It really sucks to feel strongly about a 35% candidate, bu that doesn't mean he is entitled to a party's nomination. Especially when he is openly hostile to the party.
Dispense with the charade of primaries.