I too have been a long time fan of the thincrust Shakey's pizzas.
While your pizza looks great, I might suggest a few experiments for you to adjust it for a crisper center.
1.) I usually parbake the crust a bit for this kind of pizza before putting any toppings on it. Seems to help dry and crisp it a bit.
2.) I think your pizza looks good as is, but again in the quest for some more crispness you might try one with a little less cheese, sauce, toppings. You may be over loading it for the center crispness you want.
3.) Adjusting time/preheat/and oven temperature may help in some way. Probably too many ways to plan for.
4.) I seem to remember Shakey's having a fair amount of cornmeal on the bottom of their crusts. I do that most of the time now and I think it raises the bottom from the stone just enough to help let some moisture to escape from the bottom.
5.) Nothing to do with crispness, but I seem to remember that the Shakey's sauce was noticebly brighter/tastier than most other pizzas in our town. There aren't any Shakey's places anywhere in the midwest anymore. Probably been over 20 years since I had one. To get near that extra bit of zing in the sauce flavor, I still add a bit of sugar and a small amount of vinegar to my 6 in 1 puree. The 6 in 1 puree is the brightest tomatoes I have found to date, but I still perk them up for pizza sauce with that touch of sugar and vinegar.
I am not the pro class that some of the other posters are here, but most of my friends and family think my pizzas are better than anything that the local eateries are putting out. Try a few of these simple adjustments and keep us posted on your progress.
Good luck and Have fun and keep us posted with pics, procedures, and recipe details whenever you can.
John in Merrill