The buffs to the assorted Soldier banners over the past few months have definitely been necessary ones, since before this series of balances and reworks, the only real viable banner was the Buff Banner.
The Battalion's Backup is a pretty situational item in my opinion. A pocket sacrificing his Shotgun for the Backup would only be viable in my opinion in pushing a heavily fortified last, since the nullification of Kritz, reduced Sentry damage, and just reduced damage in general would be a great advantage to push onto the cap.
The Concheror is less of a situational item and a bit more of a wildcard item. Its passive HP regen is fantastic in some ways and a bit of hindrance in others. It would allow a Pocket a bit more freedom in rocket jumping and allow him to get a bit more aggressive than he normally would. The only downsides I can think of is that if someone ever decides to try and run Conch to mid, their rollout is going to be slow, as the HP regen is passive and goes through the Escape Plan, slowing the Pocket, forcing them to be slow or shoot a rocket at themselves to gain more speed. It would also be a pain to build with a Soldier who's gaining an extra 2 HP back per second, slowing down the uber building process.
The pros outweigh the cons though, and I feel Valve did a great job with making the other Soldier banners more viable in both public and competitive play.