First, I would say that your subjective opinion on what speakers make you happy is ALL that is important.
Second, any hi-fi salesperson is going to find what they think is the weak link (in your system or your mental armor) and exploit that for a sale, albeit that doesn't mean you shouldn't ever at least consider their input;
Third, if you have any concerns about whether a different speaker could be an upgrade, borrow them and listen. Any salesperson who comments on a weak link should be willing to lend them out.
My $.02, I had a pair of cheaper MLs and I didn't really like them, but the room placement was totally sub-optimal. I didn't give them much of a shot before I moved on.
I will also say that a big Magnepan like the 3 series, especially with added woofers, isn't that short on bass. It won't necessarily push your hair back but it also has a beautiful character totally distinct from cone/box.