There are places where the weights aren’t great. But in general, I think this is more of a rigging issue than a weighting issue.
Places where the weights aren’t great: head and body. The main bones don’t have enough influence. Leg manipulation affects the entire body-- even over onto the opposite side’s leg! Shoulder manipulation is way too strong. Brow manipulation makes the whole skull collapse. Tongue bone affects all the way to clavicle. The body and the head need to be affected less by relatively minor bones.
Eye weights also aren’t great. A t-rex doesn’t have to express shock, disgust, or love, but he needs to blink. Demo the blinks.
But rigging is the bigger issue. Tail weights are actually fine, once you get away from the body-- but why do you have some weird shadow of the tail, with different bone lengths, and then copy rotation from it? I think that Muldoon probably saw these shadow tail bones, saw that the mesh didn’t agree with them, and chalked it up to weights, when really, it’s just some weird junk in your rig. (There are a lot of other unused structures in your rig.)
That’s harmless, just confusing. There are other rigging issues that aren’t so harmless. The jaw bone rotates around the wrong place (too anterior). “Shoulders” rotate around the wrong place (too high).
Finally, modifiers. Test your weights without corrective smooth or subdivision. If you want to include a subdivision modifier in the file, put it after the armature, not before.