I think that the Covenants weapons they get in the beta are more powerful than the spartans because by the time they are fully upgraded they get to chose energy swords, plasma grenades, and needlers. Also when I play invasion most of the time they win because they can easily take us out with the needlers and plasma swords as we are going after the guy with the core.

I disagree. Spartan shotguns beat swords every time. Its the same as in Halo 3, plasma takes out shields and human weapons take out health. Frag grenades have a ridiculously huge radius, more than balances out the sticks.