While in FTL Classic boarding was the best way to win and achieve a decent score with all and any ships, this has very much changed for AE, at least on Hard. In AE Hard, boarding doesn't give significantly more scrap (often, you just get lots of fuel and a meagre scrap reward), and is risky, as enemy ships frequently have reinforced doors and jump away when scared and almost always carry at least one missile launcher, so you either need to complement your boarding party with strong weapons to deactivate missiles, cloak missiles - not really possible for extended fights with most missile launchers, evade missiles or have a Defense Drone installed to avoid substantial damage or the loss of your boarders because the enemy missile happened to find your teleporter. Losing your boarding party is extremely bad, as crew is very hard to come by.
Then, the teleporter occupies one of the eight possible installed system places, and since pretty much all other systems are more valuable for ensuring survival, it's better not to buy a teleporter on a ship not coming with a teleporter. Incidentally, teleporters are more expensive now as well.
I still wanted to get a teleporter for my Bulwark run, to get the fire boarding achievement and unlock the Shivan. And here comes the next reason why boarding is no longer a viable option for ships not having a teleporter preinstalled: teleporters are not found in shops very often anymore. Run in case found the first teleporter for display in sector 5.
In the end, I got cloaking and hacking instead of a teleporter, and still managed to
scrape by, but didn't unlock the Shivan.
So if you don't find many non-depletive weapons, you can also go for hacking the shields to let your few laser or beam weapons through. If you don't find *any* non-missile weapons before running out of missiles, getting a teleporter may still be the best option. If you don't get any of these and run out of missiles because they are miss-iles, then you are just having a very bad run and can hope for better luck next time
