first, all those you mentioned are immigrant lawyer, not litigate lawyer, there are totally different field-- image you ask hardware engineer for software program ?
Unless in very anti-immigrant Courts, now with the name check memo and well-established Court ruling, it is much easier job to solve your delay case through WOM, assuming:
1. your PD is current
2. your I-485 pending over 1.5-2 yrs
3. you can show that you have exhausted administrative remedy, such as write to senator, FBI, USCIS, infopass etc.
Whether to hire a lawyer or DIY (call Pro Se), it totally up to your own situation. Someone prefer lawyer to save time (or not so self-confident), someone prefer Pro Se to save money.
There are lots of cases analysis, step by step information for Pro Se WOM, see WOM infomation