What has happened since then:
1. Mechinical Creeps. In the 3 lane creep waves, The Sentinels get a Glaive Thrower every 6th wave while The Scourge gets a Meat Wagon every 6th wave. They are very good at damaging towers so protect them if you can.
2. Alchemist's ulti, Chemical Rage, had it's health regen nerfed. Spectre got buffed and is very deadly.
3. 5 new items
(a) Vladmir's Offering - 18% life steal aura along with a Devotion aura and some + dmg. But the BIG thing is, the lifesteal is NOT an orb effect! And it only costs 2400 to make. This is so damn good late game. (Requires Mask of Death + Ring of Basillus + 1000g)
(b) Hood of Defiance - +8hp health regen per second and 30% magic resistance. ([Ring of Health or 2 Rings of Regeneration] + Helm of Iron Will + Plainswalker Cloak)
(c) Arcane Ring - +3 armour, +300 mana, 15 mana cost activation to get 135 mana back, cd = 30 seconds. This is SO GOOD. (Requires Ring of Protection + Mana Booster + 525g)
(d) Bloodstone. 500hp, 500mana, hp and mana regen boosts, reduces time spent till next resurrection by 40%, can stack up to 10 times to reduce death time, charges lost every time you die, charges gained every time you kill someone. (Requires Soul Booster + Perseverance) VERY handy on int heroes late game.
(e) Mjollinr. +35agi, +35 damage, 20% chance to cast Lightning Bolt upon attack, Static Charge (activated, reflects damage back). VERY UBER on ranged agi heroes. (Requires Eaglehorn + Maelstrom)
4. Aegis is no longer made via items. You can only get it by killing Roshan. Roshan has been nerfed heavily though, you can kill him much earlier in the game and he respawns about 15 mins after is killed. He drops Aegis first two times, then from his 3rd death onwards he drops Cheese (restore 2500hp and 1000 mana). Aegis is stackable. However Roshan now only gives all players 200 gold instead of 800 gold since he is so easy now. Meepo, Ursa, Juggernaut or Drow can solo Roshan early if they itemise right.
5. (THE BIG CHANGE) 6 new heroes were introduced in 6.44.
(a) Sacred Warrior. Strength. 2 of his abilities cost health rather than mana (Fire Arrows + Bleed Stun) while his mana move is a major heal move that can't be interrupted. The more health regen you get, the better he is. He sucks versus agi late game though. He's a good tank and has a very good ulti, his heal can be cast on allies as well as him. But he's more a mid-game hero. Late game he gets owned. Needs some fixing.
(b) Undying. Intelligence. Yeah...That's right...He's a zombie and he's INT. Explain that. He has a -%health aura that makes all enemy heroes within range constantly lose health. He can spawn mutliple zombies that hit fairly hard and they regen Undying's health when they die. His ulti is a major slow. Early game Undying is insanely good at tower pushing but unless you push hard early, he becomes a huge liability. Needs a major fix.
(c) Dark Seer. Intelligence. This guy is weird. He could be good soon. He has a move that removes all negative buffs and gives a temporary movement speed burst. He has a shield that burns anyone that is within range real hard. He has a vacuum that sucks everyone back to him and hurts hard. His ulti is a portal wall that anyone who walks through it gets duplicated. If enemies walk through it, their duplicates turn on them. Potentially good but he is just a major liability late game. Needs fixing.
(d) Pit Lord. Strength. He's okay. Rain of Fire does good damage. His trap lasts up to 8 seconds and can impair all enemies rather than just 1. His Corpse Explosion move can be a very clever trick. His ulti allows his entire side to portal anywhere on the map, very good for late-game pushing. He doesn't have good damage himself though. He's a good team hero but will get massacred alone. Needs a bit of fixing but a good concept.
(e) Templar Assassin. Agility. This hero is fun but hard to use. Passive move that has attacks pass through a primary target and hit anything behind it. Meld allows her to go indefinitely invisible and do a high dmg attack to her next target if it's within range. She can do a temp shield that makes her invulnerable for 5 attacks. Her ulti is Stastis Trap, can lay 11 anywhere on the map then activate them to slow targets by 50% for 5 seconds. This one requires a lot of coordination and timing. The problem with Meld is people know EXACTLY where you are and if they have AoE moves or wards, you're in big trouble. If you can farm with her, it's good. if not, liability. Might need a fix but a good idea.
(f) Storm Spirit. Intelligence. This hero is the one they got right. He is brilliant. Passive that has a chance to cause extra damage and slow to other units around attacked target. A shield that blocks a lot of magic damage. A move that increases attack speed by up to 80% but constantly chews up mana to keep it going. Ulti is to jump 600 range and pull any other allied heroes with him. Get some dmg and mana regen on this guy and he is amazing. If you get Eye of Skadi and have the mana regen to perma fast attack, no hero can escape you unless they're stealth. I've managed to kill a full team 1v5 with this hero, he is very good. You just need to survive and farm early then mid-late game, he will be an absolute powerhouse. Leave as is, brilliant hero.