Are there times when a hand with a seven card suit is too strong for a three level pre-empt?
An opening bid of 3 spades shows a somewhat weak hand with 7 spades. A hand like AKJxxxx Ax xx Qx would certainly never open 3S. Partner's hand in first or second seat is worth a 1S opening in my book; it's certainly better than any balanced 12-count. In third seat I might open 3S, since game is unlikely (partner is a passed hand) and LHO might have a good hand and guess wrong about how to proceed.

Personally I would have risked a game bid with your hand, at least at some forms of scoring (eg vulnerable at IMPs). Game is a good bet if partner shows up with the hand you expected. You'll expect a loser in hearts and diamonds, with some chances of shaking a club loser or two on the red suits. You'll run into a bad time if partner had a spade suit headed by the KJ and nothing outside, so when your side has favorable vulnerability, the raise to game may be ill-advised.