Are you sure about that?
Even cloth armor builds can hit 180+ PRR without too much trouble if they don't dump defensive feats and APs. If they're planning on running reaper, they most definitely shouldn't be dumping defensive stuff.
- 50 - Enhancement bonus - RL gear
- 24 - Insightful bonus - RL gear
- 12 - Quality bonus - RL gear
- 20 - Adherents of the Mist set bonus
- 10 - average from mythic bonuses on various gear
- 6 - 2 tiers of Reaper APs
- 9 - 3 epic/PDK PLs
- 20 - Heroic enhancement trees
- 30 - Master's Blitz
That gives a total of 181 PRR from a pretty reasonable assumption of gear, PLs, and APs on a cloth armor build without any intentional min/maxing for Reaper. Light armor would add 20-30 to that depending on BAB.
Anyone wanting to run a low PL toon in cloth or light armor in high skull reaper should obviously prioritize PRR and bit more and should be able to crack 200 without sacrificing too much in other areas assuming the build is good.