Tiers have never been far apart in VF, mostly due to how the system works. It really depends on the player to have a strong defense. VF5 ver. B is definitely not as balanced as Evo or FT though, but ver. C will probably be on par with those balance-wise.
For anyone beginning to play Evo in the day, I always put stress on learning to fuzzy guard, and now in VF5 it is even more important because you can fuzzy in many more situations. I believe you can fuzzy guard up to -6 (-7 if you crouch dash) in VF5, so you have the opportunity to use it a lot, as well as just out in the open.
The basic idea of fuzzy guard is to crouch, then stand back up, avoiding both an immediate mid or an immediate throw. The concept is that you’ll stand up in time to block a mid, but throw is faster so you’ll still be crouched when it grabs.
There are 2 general types of fuzzy guard. One is fuzzy guard by timing, which I think is what most people learn and depend on. This is doing fuzzy in the appropriate defensive situation, just going by the timing and not necessarily watching the opponent, but focusing on the timing to avoid an immediate mid/throw.
The other is reaction fuzzy. This is harder, but stronger in my opinion especially if you can train/condition yourself to see certain things that would normally beat fuzzy. Here you would stay in crouch until you see your opponent do something, and then stand. As long as you react in time, you will block the mid, but throw is fast enough that you shouldn’t be able to ‘react’ to stand up into the throw.
Things that can beat fuzzy are low throw (this is the absolute best option because there is really no way to react or ‘take back’ your fuzzy to beat it; you might be able to evade or attack out of it on reaction if you are very fast, though), fast low attacks like the basic 2k, and delayed throw. Delayed throw can be done in a lot of ways, like dash throw, crouch dash throw, 8~33/66~throw, K~G cancel -> throw, etc. Basically doing something to make someone ‘react’ and stand up to be thrown. In my opinion K~G cancel throw is the hardest (virtually impossible) so fuzzy against and actually stay crouched. Dash/cd throw is pretty easy to ‘un-react’ and stay in crouch against. 8~33/66 or movement tricks are sort of in between.
Also, if you have a strong fuzzy guard you should be able to not only avoid mid/throw, but also be able to block immediate sweeps/slower lows (~18F) on reaction. If you can do this then people will have an extremely hard time doing any damage to you, because they can’t easily put you in a forced guessing game situation (un-crouchable throw) like VF4.