Strange release for me. The new stuff BT got is so paltry that I can't see why they weren't in the IF supplement. Looks like they were just used as the Imperium faction to ensure players on this side bought the book. Compared to the well thought out stuff we got for RG, UM and Sallies which is fluffy yet powerful it looks like this was phoned in.
All the additions to advancing, charging, melee bonuses etc are good looking on paper but this is a shooting edition unfortunately. We'll see the real extent when people are trying to get Crusader squads in a single LRC across the table against a Tau/IH/IF/Eldar castle.
The only thing the book tells me is that BT are now considered much lower down the food chain by GW, no matter how loud "we had a codex in previous editions" is shouted.
Considering that the Templars now have ways to help keep LRCs alive better, deny overwatch with their help, and multiple ways to boost your ability to close the gap then any mission that can't be won by sitting in your deployment zone firing guns is going to work quite well for them. The question is going to be just how well does all of it work in practice and what will the Meta look like in the near future.
Also going by the rules at the moment Black Templar also have full access to the Imperial Fist rules as well. I expect that to change in some way but it has't yet.