So here is the thing. Our chapter tactics and "super" doctrine do not allow us to take a large chunk of the codex's units efficiently, since they have a transportation problem. Transports cost points. Points are precious for our lists and our return on investment on them isn't always the greatest. But if our units cannot get to the enemy, we are not able to access our doctrine. Close combat kills and tying up our opponent in assault is how we win the game. We are not suited to long firefights. So, we're going to get a lot of use out of Elites and Troops slot for this, coupled with some deployment shenanigans.
No list will be effective without SOME firepower, if only to kill blocks of infantry at least. Thunderfire Cannons come to mind for this, as can Inceptor squads. You can even combine roles in this effect with units such as Assault Centurians, Company Veterans, and/or Invictor Tactical Warsuits as examples. Likewise, Eliminators and Suppressors feed very well into what we're trying to accomplish with our lists. The former eliminate key enemy HQ units and the latter ensures you get to combat intact. However, with that being said, some of the most successful lists out there right now in tournament play do not have large shooting contingencies. It is supplemental. Players are using close combat to deal with vehicles or other issues in their lists. Notable exceptions are Iron Hands lists and drone-spam Tau. Nevertheless, if we can get to the opponent with our units, we stand a good chance of winning with our stratagems.
The key going forward is that we need to be in combat right away in the game. Like first turn, right away. We have some tools to help make that happen, but we also do not want to charge into a castle and get blown away by overwatch. We can deploy on the ground first turn into cover, using units like Vanguard Veterans backed up by litanies from our Chaplains, and potentially get a charge off first turn utilizing our new stratagem "The Emperor's Will". Jump packs are important for this, as it obviously gives us a larger movement range and FLY. That will prevent an opponent from catching you with Suppression Fire and halving your movement. With the right setup, you can get pretty much any unit across the board for a potential first turn charge. But its not something we want to build a list around, as its a gimmick we cannot guarantee in tournament play.
Fortunately, we have drop pods, which can facilitate first turn charges. This is particularly useful for Company Veterans packing Storm Bolters and Chainswords; even more so if they are backed up by a character. Putting the right unit in a drop pod can put the enemy on their back foot right from the start. There is another special rule that helps us get into combat quickly: Concealed Positions. Fortunately, the new codex has given us a ton of new units with this special rule. It is actually the basis of one of my archetypes, Peak-a-Boo Templars. Concealed Position does not always guarantee a first turn charge since you still need to be 9" from your opponent's deployment zone (and they may not be at the edge of it) as well as their units, but it does allow you to position your units in a strategic manner so that you can move into their deployment zone on your first turn and potentially make those charges.
One unit that fulfills this need is the Scout squad. For a long time now, Scouts have been one of the most effective and cheap ways to fill Battalion/Brigade detachments. Now, we have a legitimate buff source for our Scouts -- the stratagem "Oaths of Honour". This makes a 10-man unit more effective than a Incursor squad or even a Reiver sqaud in close combat. The larger unit size allows us to take casualties and still be effective, but scouts are cheap enough that this isn't a points drain on your overall list. But you can also go the Incursor route here for your troops. There really is no straight wrong answer here, so long as you are taking concealed position troops (unless you are building around blob crusader squads...but that is for another post).
The key for our lists is to overload our opponent with close combat threats. Throw your cheap throwaway scouts at your opponent to soak overwatch, then follow up with Vanguard Veterans, Reivers, or maybe Invictor Tactical Warsuits. Do your damage, consolidate further into combats to trap enemy units and prevent them from leaving with "Tenacious Assault". We have a lot going for us now; outside of GSC, there really hasn't been a close combat army that disrupts like we do. The Black Templars may not be a wrecking ball in close combat (unless you're taking a rock unit), but we can do some pretty cool things once we get there to prevent our opponents from doing what they want. We just have to make sure we are building our lists correctly to maximize its effectiveness.