Good point, occurred to me, too. If the wrangles over Cruz's 2013 shamnesty amendment are any indication, the only names that keep coming up consistently in the good guys' column in the Senate are Cruz, Mike Lee, and Jeff Sessions, who is the "go-to guy" on the issue.
The only way taking one of them out of the Senate could be considered a good move would be if his next stop were the White House, or as you pointed out, the vice-presidency.
Cruz is smart. He knows the real power in this country is the regulatory state, the technocrats, etc. We need to start undoing all of that or legislation is worthless. Besides, no good legislation will come out of the senate.