I get where the other guy is coming from. While it is fun to get every star possible with a ton of cap space, it's not the same kind of accomplishment.
I did something similar last year within my house rules. I had a rule for resigning guys (based on their age, overall, and when they were drafted) as well as a rule on FA signings. The resigning rule I got off this forum, but I can't remember the specifics. The FA rule was more about controlling the position upgrade. Iirc, I'd only allow myself to sign someone that was a maximum 3 points higher on overall as a baseline. Then for every year a guy was older than the previous person in that slot, I would add one point to that baseline. If he was younger, I'd take a point off the baseline. If I don't resign that 80 overall DE who is 28, I can sign a 87 overall DE that is 32 or older, or I can go after that 80 overall who is 25. This either allows me to get better now, but adds age, or build a viable but younger team. It's all in adding extra difficulty.