The issue with me is that since I have a new manifest, I rely mostly on powers. Having the support of top equipment and weapons helps a great deal.
About the manifest, I'm getting annoyed at the quantity of character training cards I'm getting when I still have so many weapons to max out.
Maybe promoting classes might help to put those training cards to use.
Buy Arsenal packs if you want weapons. If you're buying Veteran or Recruit packs, you'll always get the starting human character cards, which are useless unless you need free XP for promoting. If you're consistently playing Gold, you can buy a Spectre pack after every game, if you get 80k per gold match you will have 240k after 3 matches. You can then buy 4 spectre packs and get 4 gold cards (maybe weapons, maybe characters, maybe ammo). Or you could buy 2 Arsenal packs, giving you 4 gold cards as well, but almost guaranteed to get 4 weapons, or at least weapons and weapon mods. Since you're buying 2 packs instead of 4, you'll get less overall cards, and therefore less consumables (ammo, amps, armor bonuses, etc), but that's not as big a deal if you want to build your manifest.