very good idea. I wish I'd done this.
The brooks t4 and t5 were great. Then they made the shoe more curved and switched the lacing to the side. I couldn't lydiard lace the t6 and t7 and they don't feel right on my feet. I'm eager to try the new hyperion racer whenever they come out this summer.
Same thing with the adizero rocket. I've tried original adios as well as boosts, the hagio, and the takumi sens. None feel nearly as good. The takumi sens and hagios have rubber nubs instead of like rubber plates (idk what they're called), built into the shoe and they lace too tight on top, hurting my foot. I don't get the same responsiveness I got from the rocket. Both the original adios and adios boost feel heavy and unresponsive to me, even if the world record was set in them. I wish I'd bought 10 pairs of rockets or so and cut out a vacation or something.
If a shoe you like is on the verge of being discontinued, buy as many pairs as you can.