There are many considerations here. I think and hope that Cruz knows what he is doing. The trick is for him to keep doing the right thing when he sees that numerically he’s close to the nomination. The best outcome for Trump (other than both Kasich and Cruz dropping out) is for Cruz to stay as long as Kasich does.
The Cruz delegates are more likely to protect Trump’s interests on rules votes than the Kasich delegates would be. Trump is better off with as many as possible of the delegates that don’t go to him being Cruz supporters who have been vetted by Cruz. Some Trump supporters don’t want to hear anything negative about their choice, but Trump has not shown much talent for recruiting and screening his delegates. Cruz has been great at that part of the campaign.
As long as Trump and Cruz reach an arrangement after the rules are approved and before the first ballot, Cruz staying in is the best option for conservatives. If they don’t make a deal, then I am worried about the convention outcome. Trump will be first place from the primaries. Cruz could possibly win an honest delegate battle at the convention, if Trump fell short on the first ballot. With the establishment intervening though, I expect a contested convention to go to Kasich. Kasich is completely and totally unacceptable.
The other consideration is that the Trump campaign team has only focused on winning votes. Competing against Cruz is a good chance for Trump to learn about the other considerations in an election campaign. They do not seem to be learning quickly, but Trump has a couple more months to continue benefiting from the lessons before he faces Hillary.
Very good points.