That's exactly my experience with them. They are years old as a design now, and while the bass is good and the 'V' shaped signature accentuates it even more, where I found they always lacked with modern music is the sub-bass. largely I suspect because sub-bass did not have a large place in music when the TF10 was designed and was therefore not really a consideration. Someone on the TF10 appreciation forums, told me that according to measurements of the TF10, they are able to hit sub-bass no problem and advised me some EQ settings to try, which I did, but still there is sub-bass rolloff. They don't cope anywhere near as well with sub-bass as my Vsonic GR07, my T-PEOS H-100 or my CE HY3, which all contain dynamics. I am well aware that modern BA's are capable of resolving sub-bass, but the TF10 isn't a modern BA.
Phil thought it would be an interesting experiment to try a Dynamic with the TF10's BA's and I agreed with him that it would be fun to try it. Nothing to lose by experimenting eh ?