I think problem is marginal.
I plaed through all but two Heroic possible for Empire (skiped one 46 and one 50 lev heroic on Corellia, still got them in quet log thou), many of them multiple times.
Not a single time had I any difficulties finding party, neither on low-lev, nether on mid/high lev. Unless you call 5-10 min on chat a difficulty or look for those at 4am.
Just consider that your playtime is not exacly playtime of majority on your serv, try tu figure out when there are more people around.
Consider making friends with people met in game, if you find company for heroic, ask him/her to join you next day on another planet, add him to friends and "whisper" when he comes online, (you will be notified of this.) In a week you will have a dozen friends on similar level. Another week and you will know who plays in similar hours as you do.
If you can make without great cost or find something usefull but not for your class (stim, piece of blue gear, mod, etc), dont sell it cheap to the medical droid or squize nickels on GTN, just give it to somebody as "a reward/quest loot" for joining group and questing with you, works great for me. These people will seak you out later because of that.
Most 4+ Heroics can be easly done with 3 players. All that matters is t have at least one long CC for Elites in mobs, without it you can have some difficulties (like 3 SithWrr, 2 tanks and 1 DPS against 5 elites, no CC longer than 4 sec at a time... it was hard. 1 Tank and 1 DPS with healing companions cut through same quest like throuh butter).
And for the end, NO! In any case dont nerf Heroics, some are little too easy, some are easy for nly given classes, in some you just need to look around an be witty, and some are stright forward murderous - like this Esh-Ka Staff Master in 43lev heroic 4+ on Taris.
I dare you to jump him on 43 lev without 4 people and some decent cooperation. I want to see this
On the other side, It is possible to do Lights Out 50lev H4 in pair WITHOUT A SINGLE WIPE (dont count companion), even without stealth to be exact
. Even more, both players were warriors, - melee
It is good as it is.
No nerfing Heroics.