Shoes. Argh.

Having gone to the running shoe store and spoken with the knowledgeable people there who remembered me from last August, I eventually walked away with a pair of Mizuno Wave Rider T1's in men's. These seemed like the best we were going to get with my feet, but when I tested them out last Monday, (before being sick the rest of the week) they still hurt the outer edges of my mid sole as if the shoes were too tight in spite of the lacing techinique I employed. Also, in spite of the lacing technique I employed, I still experienced heel slippage. I'm wondering if a) my feet will get accustomed to the shoes and break them in enough that I don't want to go wider and possibly get too much room in the toe box again allowing too much lateral movement when I leap out of the way of crazy college-age drivers, or b) the shoes will break in enough to bend more easily and thus eliminate the heel slippage such that I should not be concerned about this. I really like the wave technology that means my shoes will last the test of time and increased miles better, (since I'm still a heavier runner this means a lot to me) and I don't want to give that up, but obviously I need shoes that will work with my feet well enough to be worth the investment and the breaking in process.
Right now my runs are not long at all and I mostly only run every other day. I'm still slooowwly building up my mileage again after injury (fallen arches causing shin splints/anterior compartment syndrome for which I have appropriate inserts meaning I only need a neutral shoe) so I'm only at about 2 miles a run for 6 miles a week. I cross train with my bike for about anywhere from 15-30 miles per week, depending on how I feel that week. (We've had weekend illness a lot the last couple months.) I do plan to go back to the running shoe store and maybe test out these shoes a bit again before that to make sure about the issues I'm having with them when I talk with the guys at the store again. I just want to know what is realistic to expect and what is not. I have only purchased one pair of running shoes before and those were my Asics last August which while ideal for me have also had their issues. (Too long since I needed it to get the width my mid sole needed and I would prefer a shoe that will last better with the greater mileage I plan to do, meaning I want to be able to run a 10k for the World Wide Festival of Races which will be a huge new distance for me to build up to.)

Anyway, let me know what you guys think. I know I need to be the one to make the judgment call with the shoes I try. I guess I'm just hoping for some more experienced in put to help me with that process. Thank You!!