I don't dislike Trump; nor do I like him. I love that he is shaking up the parasitical GOPe and causing the politically correct to have the vapors. This is a valuable service that he is doing.
However, I don't trust him to do what needs to be done. He is, by his own often proclaimed admission, a "deal-maker". I don't think we need a deal maker right now. We need someone to go into Washington DC and kick butt and take names. To hell with deal-making. That's what the GOPe has been doing, much to the detriment of the country. Partially because the GOPe'ers don't have a vision and ideology that they understand or accept enough to fight for, and because the left's idea of deal making is that the left gets everything they demand.
I understand your point. But, perhaps you overlooked a minor point here.
A deal involves an agreement entered into by two or more parties for their mutual benefit, especially in a business or political context. But, Trump said only that he would negotiate better deals for America, not himself or the GOP.
He doesn't appear to desire either political gain beyond this race (he's an outsider to politics), or personal enrichment (he's already got money). And I don't see how he could become any more famous than he already is (he reached icon status years ago).
At this point in his life he doesn't appear to care what people think about him (he doesn't use focus groups or political consultants to tell him what to say, he pretty much says whatever is on his mind).
So, what else could he gain if he were to compromise on his stated positions?