I think things sound within the realm of typical or normal also. Delidding is something to consider if temps are high, it doesn't help with voltage. Two things limit overclocking, vcore and temps. All the cooling, delidding, high end coolers etc in the world won't help if vcore is pushed too hard and ends up damaging the cpu.
1.5v vcore is pretty high and not what I would consider safe for typical daily use. Maybe if trying to compete and achieve a particular oc while accepting risk of killing the cpu. 4.8ghz is also pretty high for 3rd gen i5's, it's pretty high for 4th and 6th gen i5's. It's not until 6th/7th gen i5's that 4.8ghz becomes more attainable. Actual oc results aren't bad all things considered, maybe not the greatest but...