The Trebuchet is an interesting mech and one of my favorite medium mechs given how well it slots into a lance- working as a support unit for the other mechs in the group, a great side-rider for your other units.
At ~1200 battle value it isn’t cheap, but not over the top for a medium mech, giving you enough points left over for other needed toys. We start with two LRM-15s which is a great start.
Firing off 15 means that with an average roll you will score some good damage on the missiles, roll legendary and it gets better. Two have the redundancy to fire every turn and score hits. Plus you have a decent amount of indirect fire on the one mech alone. Closing in we have the three medium lasers, enough to scare off aggressive light mechs, put some hurt on the medium mechs, and work in support with heavier mechs.
Options for punching and kicking are there, but as a medium mech it won’t have the impact of a heavy or assault. Given the locations of the weapons moving and shooting is better.
Tactically the Trebuchet is doing something every turn once it is in range- firing LRM, switching to lasers, and even with the lasers at danger close range firing off the LRM packs for some extra damage possibilities even if you start pushing the minimums for range.