- Hull Points means the missiles of Loganwing are more reliable against vehicles over time but don't have the low AP punching power to be really scary outside of volleys if you're looking to one-shot a vehicle.
- Rapid-fire got a whole lot better which means all those boltguns are now a lot more useful and purchasing Storm Bolters a lot less necessary. Ranged anti-infantry becomes less of an issue.
- Wound Allocation system is both good and bad for Wolf Guard based units - you have the options still to bring 2+ armor and 3++ invulnerables but you no longer have the wealth of choice in where each wound applied by the opponent goes. You can lead with such models to force saves onto them initially but there are ways around this - the simplest being shooting from the sides, etc.
- This rolls into reduced cover saves and harder to get cover for units - it's harder to fob off low AP shots onto guys running around with Stormshields now unless you fork out the points for each model. This means each Wolf Guard is a bit more vulnerable to return shooting than before, particularly against low AP weaponry where they normally would have been able to use a 3++ or at worst, 4+ cover against. Now, individual models generally get a 5+ cover.
- Snap-fire is again, nice and not so nice. It helps Long Fangs reposition and firing at a greatly reduced effect - but some firing is better than no firing. The opponent can do this as well however and this means mobile heavy weapons on foot are less awesome than they were before. Only by a tiny bit as you're still using your full BS, etc. but it's there.
- Logan is awesome. He's not as awesome as Lysander or Marneus (who, other than being awesome, sucks) but he's pretty top-notch with new character rules. He's good in challenges, helps out squads he's with and can fob rounds around whilst being pretty durable himself. Nice to have - and of course, he enables the damn build.
- RCL can hurt the Loganwing support like Thunderwolves but with their change to a base 12" move, they generally come out ahead over a couple of turns (compared o 6"+D6" Run). Otherwise, it's another nice and not so nice change for Loganwing. Your Wolf Guard units are pretty decent all-round and not bad at receiving or handing out charges. RCL brings in longer charges even if they don't happen super often - particularly through terrain. Wolf Guard units generally have decent Overwatch firepower for being small units and with some proper wargear, can take Overwatch firepower pretty easily as well, etc. Lots of give and take here again.
- Fliers - pure missiles don't really work against fliers as they aren't twin-linked and Prescience is only going to go so far with a group of four-five missiles. Unless Flakk missiles are FAQ'd in, Loganwing doesn't have a decent DIRECT damage way of handling fliers on its own without a bit of luck.
All is not lost however as the Space Wolves codex is still strong and has a lot of Ally options - Loganwing just has to become something different compared to what it was before and this is most likely some sort of Hybrid army variant or something with Allies to shore up weaknesses. The core is the same, it's just how support that core which changes. So let's look at your base template and then go from there.
4x5x Wolf Guard w/Cyclone Missile Launcher
3x5x Long Fangs w/4x Missile Launchers
Totals: 1300 points
Looks the bloody same doesn't it? We're only putting four Wolf Guard squads in here so there's flexibility for two more or two Grey Hunter units along with some extra goodies on the Wolf Guard. The Rune Priest is much more valuable currently with the increase in psychic power options and psychic might more likely across the table, he's great utility. There's then space for straight up Space Wolves Hybrid with Rhinos, Razorbacks and Dreadnoughts helping keep the Wolf Guard protected from shooting (flat-out moves are golden here) and adding extra punch + more reliable damage against flyers. Thunderwolf Cavalry are also a great unit to tie up enemy units and be a pain in combat though without any characters leading them, Would Allocation can reduce their effectiveness as whole models start dying. Lone Wolves are likewise a solid choice, particularly within a Hybrid concept, who can deal with a lot of the tougher units out there or be damn annoying to normal units.
Then...then there's Allies and being an Imperial army, there are tons of options here. You've got Black Templars, Blood Angels, Imperial Guard and Space Marines all as good chums and Dark Angels, Eldar, Grey Knights, Sisters of Battle and Tau as half-good chums with only Chaos Daemons/Marines & Tyranids as absolute no-nos. That's a hefty list though we're really looking for something which is going to solve the identified problems and not everything here really does that... Let's take a look at a few who could.
Imperial Guard: Can pretty easily get some extra scoring power & shooting to back-up the foot Space Wolves as well as grabbing some more vehicles. Importantly, a lot of that firepower can be twin-linked to be more effective against flyers and you can get a lot of board coverage through sheer weight of bodies.
Space Marines: Odd choice but can effectively double up the anti-air options Space Wolves have available by bringing an extra two Rifledreads with a MotF. Tacticals can help support the Wolf Guard with combat squadding melta teams as well. Oh & Khan with TWC. Fun times.
Grey Knights: Can likewise add extra Dreads, though the Venerable one is particularly expensive within 6th edition due to Hull Points, and can also add some cheap Razorbacks to help with twin-linked/middling strength firepower with Psybacks (or Passbacks). Strike Squads or Henchmen squads for cheap can work here though getting two full Strike squads in for combat squadding is going to be expensive.
Tau: Keep it foot and bring on some Broadsides + Crisis Suits with backfield scoring Fire Warriors. Crisis + Broadsides are decent against flyers and provide a lot more firepower. The entire army is still more susecptible to low AP firepower than before but that's a lot more firepower with increases in diversity as well. Could try and go Hybrid this way as well with Rhinos + Rifledreads but points would be tight.
Loganwing has to change to keep up. Hybrid and/or Allies at the minimum to overcome some of the main issues presented to them with 6th edition (i.e. cover changes). It's not a huge smack in the face but the army is generally going to look quite different on the tabletop I feel to minimise the impact of those changes. In essence pure Loganwing, or pure foot Wolves really (still), are going to suffer but changing that dynamic should see it function well as 6th evolves - especially if things get FAQ'd for Flakk Missiles.