Fighter battles don't have to consider shifting weight distribution and fleshy mass. The best practical effect to achieve that would be possibly suitmation, and even then you're limited to only humanoid shapes. If you wanna monster with a thick, heavy "knife-head" like the one in PR, good luck finding someone with the kind of neck muscles to support that kind of weight. The only reason why Godzilla did so well in suitmation in the 60's and 70's was because the design was drastically changed to look less heavy and realistic than it's 1954 predecessor. Prior to those changes, actors would pass out from heat exhaustion in just about every camera set-up and cups of sweat would be drained from the suit. So you would either have actor abuse or compromised creature designs. Take your pick.
And then there are water effects, which can never really be miniaturized without at least some CGI assistance. Even LOTR had to use digitized effects around the practical set for the dam breaking in order to make everything look adequate.
The best result comes from the CGI effects used in the PR movie. And this is coming from a man who generally likes practical effects in Hollywood movies. That is, unless of course you wanna take the other route and have Stan Winston Studios build a large-scale robotic animatronic for the movies. But that would be staying as true to the original Toho kaiju productions as using CGI, so nothing of importance was really gained in the nostalgic sense. Usually that kind of stuff in modern cinema is a throw back to late 80's high-budgeted American movies, not lower-budgeted Japanese pulp fiction flicks.
Tat being said, it would have been interesting to see some animatronics at work in the monster effects. But CGI is at the point where the visual results would be just about the same. (And even then the rain and other water effects would still have to be CGI in order for it to look properly miniaturized, most of the fight scenes would still have to be CGI due to the cinematography and attention to the musculature of the animals, ect.) In general, practucal effects would be more for the sake of the actors than it would be for the sake of the audience, and there were no scenes that could be shot where an actor could look at a life-size, fully functioning kaiju animatronic; not even segments of it for close-ups. The creatures were to big to practically build in order to be of any benefit to the actors. (Hence why there was more effort put into making the cockpit a practical effect, and not the monsters themselves. The actors benefited from that more than anyone else.)