I'm talking about nowadays obviously. He'd be under Tsonga/Berdych/Soderling without a doubt and would have no chance against the Big 4, more often than not.
Andy is superior to Ancic in almost every way except for net play and even then, it's pretty close when Andy plays well in that department. Ancic wouldn't threaten Andy at all in today's game.
Ancic's net game was soundly superior to Murray's. He also had a better serve and forehand. But that's beside the point here, point is how can you be so sure he'd be under those guys, did you watch him play in his early years?
It's tough to tell because, like pointed, the three players being mentioned have been evolving as the years passed while Mario had to stop, thus leaving a BIG question mark in relation to the topic.
I think there's a bit of a display of overrating in the opening post, Lenders, since Ancic was from the 'huge hitter from both sides' you're trying to portrait. sure, he had power and could do damage with his groundstrokes but the difference between his and the other three in that department is way more than just 'slight' (talking about power). Even if i was way younger between those years, i'd still watch a lot of tennis back then and i'm glad to have been able to see Mario in his peak, was a fun player to watch but never really thought of him as 'the next big thing' or remotely close, more like a solid top 15-20 player with some short stints in the top 10 for the rest of his career.
While it's fair to say he was probably more well rounded and consistent, with less 'clear' weaknesses, he also lacked the huge weapons the other 3 do have (Soderling and Berdych clearly had more raw, natural power back then than Ancic and out of the three Tsonga is probably the one that benefitted the most from maturing and increasing shot power as the years went on). You're also exaggerating in regards to his general speed/movement IMO, wasn't as good and his extremely long swing on his forehand (not proportional to the speed generated, Burrow spot on there) halted him to get out of difficult situations on the run with big winners, etc.
As Croat123 said, you're assuming he'd not develop. He was way ahead of his three age peers before his injury saga began. Granted, they have made big strides in their game to get where they are now, but who's to say Ancic wouldn't? It's very tough to argue he had maxed out his potential before his 22nd birthday. If you were to ask this question in, say, 2006, I'd say most people would predict Ancic to be the best of his age group and with good reason.
You thought Mario would be a solid 15-20 player with short top 10 stints? He was better than that before his jetski accident that sidelined him for several months in 2006 (and kept him from entering the TMC), he was ranked inside the top 8 and had only lost to Federer in the previous two Slams. You think he'd get worse as he aged?
As for his movement, it was underrated. Unlike Berdych or Soderling, he was capable of grinding out matches where his weapons weren't working even against very good players. The prime example is this match against Murray in Indian Wells during his last comeback attempts. People who watched it will surely confirm this is one of the ugliest matches you'll ever watch. His match with Verdasco at Wimbledon during his last hurrah in 2008 is also a good example but can't find highlights for that one, Mario was capable to win important matches even when his weapons were not firing: