I've forgotten the patches, but I played both before and after synergies were implemented. I didn't get as far without the synergies (level 69 or 72, I can't remember if that was my Necro or Din) and it took a hell of a lot longer, but I was also playing on US-West where there were a lot more stupid faggots who simply outraced the Necro in the final stretches. I couldn't do runs like I could post synergies because the mages and barbarians would just get there so much quicker.
After synergies were implemented I said goodbye to the US gates permanently and went to the European one, where I leveled up at a holy fuck amazing rate and got into the top 20 for Necromancers. The strongest guy in the whole gate was only level 91, and he was a poison necro and wasn't that great at killing other players.