Yes, its still a pain and not completely flawless tactic, but with time and space it works no problems on any difficulty!
Regarding the Patriatch, the closer he is to you, the bigger the threat. His worst combo is a melee attack, followed by a chaingun combo. However, at distance, he isn't able to melee you and his ranged attacks are much less accurate and effective (make sure you have cover from rockets, they still hurt!)
Therefore, the best strat for pat solo is to keep your distance and use a weapon that is easy for
you to use at distance. ie. xbow.
Everytime he runs towards you, knife out and run away, keeping as much distance between you and him as possible. Only stop to shoot (aim for his glass eye, its his headshot hitbox) when you have a long corridor ahead of you, which ensures the distance is maintained! Don't be afraid to weld doors to buy yourself some time, he must stop to blow them up, gaining you vital seconds in tight situations. It's all practice, experience and good decision making when to fire, and when to run like hell!
If you become a confident berserker, then you can actually melee the patriatch on any difficulty by using similar techniques to the fleshpound.
The trick is to close in and damage him with a melee attack, quickly backpedaling to avoid his own attack. He will come at you again, damage him, avoid his attack, rinse and repeat. It is very difficult and since you don't meet as many patriatchs as fleshpounds, practice is harder to come by. However, keep at it and this fun little tactic can prove to be very effective, however crazy it may sound!
Add me on steam if you require any further advice, i'll do the best I can to improve your knowledge/tactics for KF
Cheers
ljM