I play the T400 irons and I love them. Yes its good for avoiding heavy/fat shots. They are game improvement irons.

Even with the split sole, it is not as easy on a tight lie as a T300.

I don’t find a difference on fat shots between T300 or T400. A bad swing is a bad swing.

Went from T400 to T300. The mass of the T400 was harder to dig balls out of deep rough than the T300.

The T400 43 is the same loft as the T300 P. I find the T300 an easier transition from my 48 Vokey than the really wide sole 43. But it was fun hitting the T400 7 iron 150 yards.

The T400 line is considered the most forgiving of the T series irons; some would call it super game improvement irons. The new line of T series irons go from T100 - T300...there isn't a new T400 at this time.

As for avoiding "heavy/fat shots", the T400 has a lot of offset which should help avoid those shots.