Yeah I've kind of had the same experience. But I don't think its gotten really much harder to solo stomp, its just you have to make a few adjustments. The metagame has changed ALOT, so pubstomping just isn't the same.
First off you really want to pick a hero that can stomp the current most popular hero picks middle while also being able to carry lategame. I've noticed that Nomad is picked for mid literally EVERY SINGLE GAME. So I've built up a strategy kind of around that.
So far I've found the best options are:
Fayde (yes she's not a hard carry but mid/late game with Puzzle3 she totally crushes. Only really really late game does she become useless)
Zephyr - obviously dominates melee heroes that people usually go mid with (nomad, pebbles, dev), and has very very good carry potential. only problem is he can't gank that easily
Magebane - dominates almost any melee hero mid. No mana = bye bye. Also if played well can slam some bad players on ranged heroes too. For mid I would go vanguard -> phase -> manta build, since battle fury is really more for emofarm sidelane
Revenant - If the enemy team doesn't hold hands as 5 and doesn't buy eye / wards, this guy is definitely the best pick. Sadly the current metagame kind of revolves around people being super gay and travelling as 5 always, but with a little teamwork you can overcome this as well. Basically, Revenant's 1st skill lets him harass the fuck out of any melee hero anytime they go for last hit. Also he has invis to avoid ganks if their mid starts crying. Additionally, he really starts to shine when you have maxxed 1st and 2nd skill and 1 in invis and a hellflower. You can just invis up to almost any hero, pop hellflower + 2nd skill + 1st skill on yourself, and kill them within seconds. This works especially well versus gay S2 heroes like Nomad that have a million escapes. No spell casting = no escape for you bro. Finally, once you get harkon's blade + hellflower + nullstone or something, that hero hits so fucking hard its like unstoppable.
Nomad - obvious reasons. like 3 potential escape spells, very easy harass, prtty easy rune control, mass burst damage, carry potential, etc. He's so fucking gay I refuse to play him unless I random it because I really hate his playstyle but he's definitely a viable pick. Will also stop that faggot on enemy team with 90% played Nomad from picking it.
Arachna - Personally I think this is an amazing hero which has alot of potential. Can basically do everything you need: harass lame melee faggots, own invis heroes (Fuck you nomad), gank lanes with good rune (invis/haste = eZ kills), and hard carry lategame. For arachna, I wouldn't go the ganker build of like phase / shroud / bkb. That's fucking gay. Just build her exactly like Drow Ranger in dota in terms of items. Steamboots first, then helm of dominator. Dominate a vagabond leader / catman first. Use it to creep your jungle's small camp every minute (this alone gives +100 gpm roughly). Then get another creep after cooldown is up (minotaur / catman is best). With those 2 you can creep some hard camps too (Roughly +150 gpm). Finally, get a third creep and u can creep entire jungle. Over 200 gpm additionally if you do it right. Meanwhile you should go for firebrand -> bkb if necessary - > geo bane, then savage or wingbow or something. You can outcarry almost anything since your GPM should be through the roof if you do the jungle creeping correctly. Also you can dominate early/mid game since at level 6 you can rape most heroes mid / other lanes.
Tort - as you mentioned its a good pick. Just focus on getting ALOT of farm and owning them mid game. You become worthless way late game so end it before 40 minutes.
Drunken Master - obvious reasons. This hero is just fuckin insane. If I wanted 100% wnrate I'd just play him every game. He has everything you need. If enemy team isn't coordinated, you just get bulwark phase shieldbreaker and 1 shot people you find alone. IF they are, just keep farming. Get bkb riftshared shield bulwark etc. and rape them in teamfights.
What's unfortunate is all the old awesome heroes like SS / hag / DR just aren't as good anymore due to the public metagame of "oh we hold hands 24/7 and roam as 5 and gank mid and pick S2 heroes for mid which require no skill to do well with". But I think if you keep trying to play the old pre-2.0 pubstomp style in today's game you won't have anywhere near as good results.