i like it the best of all of the robots you've posted so far. try experimenting with different weapon for your hammer heads. keep in mind that rotated correctly your extenders have two attachment points at the end, so you could have two spikes without even adding a splitter on the end. a good idea ive found fore effective hammers is not only having a solid, fast drive (something you've already found out) but having a well protected and weaponized front end as well, to double as a rammer if god forbid you lose your hammer. a small wedge well placed will also do wonders for the effectiveness of your robot
best of luck buddy! keep em coming!