Practical every time. CGI is best used to enhance an effect rather than to do it altogether.

Practical all the way. With maybe a bit of CG to make it look better.

It depends on how well they balance the usage of both methods.

This, pretty much. There are some pretty neat moments for both of them, but also awful ones. It's always a pain to see the poor suit actor trying to move in one of those clusterfuck robos in Super Sentai. Engine-Oh G12 and all his crazy gattai friends look better in CG animation because you don't have the feeling that the person inside is struggling and it gives the mech the agility a robot should have.
What I really hate about CGI except from that horrible fighting scene at the end of Movie Taisen Ultimatum is the CGI explosions though. The Gaim soccer movie had this scene where Gaim was riding a horse through a sea of explosions and some of them looked as if they would instantly kill the two if they were real based on how they were placed. And it felt like a stretch that a horse could stand so many of those and so close without going completely nuts and ultimately running for it.

The best looking CG that I seen in a Japanese live action film is the Space Battleship Yamato live action movie from a few years ago. Even the best looking CG in Kamen Rider still looks meh at best. Japan should stick with practical effects in my opinion.

Well, that's most likely due to budget and deadline reasons. Of course the CGI in a planned out, relatively high-budget film is higher than in a weakly kids show that's part of an on-going franchise.
If we didn't have CGI in toku though, many shows couldn't have been realized the way they were and I think that would be a loss. Also, even though it's not jaw-dropping, the CGI did improve over the years- you can only learn by practicing, after all.

Honestly, I think CGI is an improvement to tokusatsu, but only when used to complement the practical effects, not replace them in its entirety.

When I watched the pre-CGI era liveman, I put many of the mecha battles on fast forward, as they felt really identical to each other: Just two giants wrestling for a bit and then the robot using stock footage as finisher.
Part of the appeal in newer tokusatsu is the hero(es) unlocking new abilities/weapons/mecha from time to time. CGI has the power to make these abilities look distinct from each other, making many of the fights unique.

A good example for me is Kamen Rider Ryuki. While the early CGI looks bad, it does give each rider and his contract monster a unique fighting style. Compare the rather graceful style of Ryuki to the more pragmatic and ranged style of Zolda, which are both accentuated with CGI. In this case, the CGI is used to complement the battles, as the Riders are still people in suits fighting each other.

An example where CGI just went plain wrong was the third season of Garo, Garo Yami o Terasu Mono, as all of the heroes' armored forms and monsters were CGI creations, instead of real suits. The exception is a cameo of the original Garo suit near the end. In this case, the CGI almost fully replaces the practical effects, ruining the illusion these characters are 'real'.

To conclude: I consider CGI an improvement for tokusatsu when it is used to complement the battles. If the creators don't use CGI, we'd still be stuck with wrestling matches between boxy robots and monsters, finishing the fight with the same stock footage every episode.

I thing CGI improves and the right amount makes it awesome. The only example I can say of a good amount is gokaiger or possibly ninninger.

Honestly, I didn't get very far in Gokaiger because there was too much CGI. I couldn't enjoy the fights because I felt like I was watching nothing. It all just felt so fake and insubstantial because of how much CGI there was.

I really don't see your reasoning there.