Possibly so. But you can argue that it is more a measure of who is the most desired students and who can cope understand pressure. Particularly with how A-Levels are going with the proposed plans that all exams will be at the end of year 13. There will, unfortunately, be students who are intelligent but won't be able to cope with that system. In fact, the stronger your desire the more likely you are to put pressure on yourself. A lot of students simply won't be able to cope with that system and I strongly disagree exams should all come at once, that being a key reason.
It also depends on what you define intelligence as. Degree level is obviously harder and someone going away, putting time into their studies and developing their own arguments and essays is probably has more of a focus on intelligence than someone who is reading out of A2 Religious Studies the arguments for and against the cosmological argument and simply converts that into an essay. A lot of A-Level performance will depend on the school, teaching and of course a lot of students and staff will guess questions and predict what is coming on, so there is obviously more luck involved at AS.
Although degree difficult with vary from subject to subject and university to university, you'll struggle to find any subjects where the 2nd or 3rd year in particular are easier than A2.
Degree is much better, in my opinion. Both demonstrate different skills though.