You ought to care about his success in implimenting tax cuts. It serves as an illustration that the President is an ally on this issue.
The only reason they were NOT made permanent is because the SENATE stood as an obstacle. The President and the House were solid allies. You wish to pressure the President, fine. I consider it a waste of my time that can be better spent leaning on relunctant Liberal Republicans in the Senate.
Further, those tax cuts helped shorten a recession that does dampen the economy which does negatively impact every American citizen. Certainly it is only a short term solution, permanence is needed, but it is and was better for the country then no tax cuts at all.
As to letting him "play" with other ideas, Pfft. You may not have any interest in other platforms he campaigned on, but I do. I do not consider, for example, S.S. reform to be a "pie in the sky" idea.
If the President were to lean on them, say by calling for permanent tax cuts, loudly and often, that would make a tremendous difference. If, as you say, he's gotten his way every time he's demanded tax cuts, then he has no reason not to push for it now. It's such a ridiculously simple task for him, in stark contrast to his wild ideas for "reforming" everything in sight. The fact that he declines to take such a simple step raises serious questions as to how much of an ally he really is.