The 737-800 is really the perfect aircraft for Thomsonfly's future for short & mediumhaul operations, considering it's efficiency, despite the fact that there is a reduction of some 40 seats. TOM is focusing on higher-frequencies to holiday destinations for two reasons it seems. Firstly, the people who remain with package holiday arrangements want more convenience & flexibility. Also, this convenience allows the DIY tourists to consider TOM as attractive as the likes of Ryanair.
I agree that the 73Gs are lovely aircraft to work on, and it wouldn't surprise me if even the larger -900 series was considered to replace some of the more high-density (LGW/LTN/MAN) routes, as well as the -700 for CVT.