you could look at the nike vomeros, or even at the asics nimbus/cumulus. I run fore/midfoot in my cumulus and theyve been great. However saucony triumph 10s are also a great option. Slightly lower in the heel, but still offer excellent cushioning, and are hugely lightweight
Asics zaraca or 33 range are excellent for mid-forefoot runners. slightly lower profile than the cumulus/nimbus, and lighter too. The fluid axis promotes a more natural technique, so the 33 range is ideal. However if you're looking for a cheaper shoe (the excel retails at £150 ish) the zaraca is again used for mid-forefoot runners, and is £70. Still offers cushioning, plus is very flexible.
The new pegasus is lighter (pegasus 29), and is a great replacement for your old ones. Fit will be very similar, as will cushioning. Other lightweight alternatives to look for that offer similar cushioning are the Mizuno wave Rider 16, Asics Cumulus 14, Saucony Triumph 10, and Wave Precision 13. All lightweight, all offer similar cushioning, but all fit slightly differently, so I'd recommend trying them all!
what I'd do is find a running shop where they can look at your gait. It would be good to see how you run, as it could have been building up over years of use, and then when the calf went, everything went with it. Get your gait checked, or get someone to have a proper look at your running style.
I'm interested in more specifics about your training - i.e how much you stretch and what type of stretches. Do you do any speed work, or just longer runs? What shoes are you currently running in/did you get them fitted/ how long have you had them? and what sort of runner are you (ie heel striker or mid/forefoot)? It could be any number of things from a suddent increase in your training load, to something as simple as getting a new pair of shoes fitted.
Let me know these and we'll see if we can get to the bottom of this!