POTUS has too much power, but so do the courts. I wouldn't mind if they ruled that a law was too vague, and kicked it back to Congress (the ones who are actually supposed to write the laws), but when they simply decide how a law should be interpreted -- that's not their job, IMO. Might as well not have Congress if laws only mean what a court wants them to, and not what the folks who wrote and passed them meant them to.
Mark Levin has repeatedly argued that the Constitution gives the Congress the power to limit the Courts' jurisdiction--but Congress has never exercised this power. (A judicial hack in Hawaii should be unable to second-guess the POTUS concerning immigration law.) Levin has also argued that broad judicial review is a monstrosity not envisioned by our Framers.
In short, Levin maintains that the Courts definitely have too much power--regardless of whether or not the judges are "conservative."
Thomas Jefferson said that the greatest threat to a Constitutional Republic is
activist judges. That sentiment is likely why the Constitution does not really give the Courts as much power as even "good" judges have claimed for themselves over time.