Here are the changes from CrazyTown that make the most difference (irrespective of bugfixes). There are alot of crazy things in crazytown, but if you wanted to keep demigod mostly the same these are the changes.
Reg
MoTB gets an interrupt
Vengance mode causes 5% movement
DA
Warp Strike gets an interrupt
DA Base Speed 6.3
TB
Firemode transition the same as Frost
QoT / Sedna
Minions scale to around 120 damage at level 4
Occ
Minions have reduced cost and scale to around 140 damage at level 4
30 Second Cooldown on the following
Amulet of teleportation
Cape of Mana
Wings of the Seraphim
Blood Soaked Wand (with 1 second cast time)
Saam-El's Cloak
10% Movement
edit: Forgot one
Symbol of Purity
Heals 500 on use
Vinling Helm
+100% mana
Explanations
Fair minions should be a no brainer to explain. Allowing the castable minion types to be around the same power level as LE/Oak allows a different way to play these DGs. (general instead of always assassin like)
TB firemode should be a no brainer to explain as well. Being able to switch and move makes a big difference for fireballing either to chase or kite.
Reg and DA interrupt
These guys need fast interrupts. Regardless what you think, fast interrupts are all around amazing at granting a power increase.
Warp Strike interrupt will undoubtedly be the most controversial suggestion on this list, but really it is a variation of a theme on all the other fast interrupts. Instead of reaching out (Oak / TB), or requiring to be close range (Sed) it is a combination of the 2. It reaches out, but puts you close range. I dunno, it probably sets of a flag in your brain, but once you play with it, you get used to it and like it.
Sure DA also has Swap, but that is not really capable of blocking something intentionally except a TP out. eg: You use it to gank, and you use it to block a TP. You don't sit on it and wait to interrupt something because usually you can't. That is where the power of a fast interrupt comes... you can interrupt a slow skill like boulder or mass charm... or it can be used to block a telegraphed move, and you can't really jig a skill unless that is your intent before you do it.
Reg and DA Speed
5% allows them to jockey for position in comparison to the other DGs that can catch and kill them if they focus on having equivalent speed. Not getting caught or chasing for a kill when its time to be mobile makes a big difference for these 2.
30 Second cooldowns.
You can use these items with 30 second cooldowns.
Blood Soaked wand is semi-strong early on for healing. (it does need the 1 second cast however to avoid excessive interrupts) and it is also strong with giants. eg: Heal 1000 on giants can make a big difference.
Saam-Els with 10% is what you pick over anklet when you face snare opponents. This item lost a purpose early on. If you install demigod without patching it, you'll see snares were alot stronger. QoT Wave had 30,40,50% snare. Reg was 10,15,20% on maim. So as snare power decreased, this favor item really wasn't necessary, as more life turned out to be a better compensation and snares were weakened. 10% speed with 15% snare protection is better than 15% speed in certain DG combos.
Symbol of Purity:
Heal 500 on use makes this item sort of like a variation of blood early on (but with a power)... 250+500 heal = effective 750 HPs. So early on, effective life while laneing can be on par with other DGs. Later in the game when a 500 heal is not as significant, the negative effect purge is like a "Freedom from BS" ability, because negative buffs get more dangerous late game.
Vinling at +100% mana regen is still up there as a non-essential item... but it does have a place over Plenor. It will combo better with Vlemish over Plenor, works better on leviathan, and still retains its good vs minions / tower rook +mana on hit ability.
Things that are probably hopeless
Staff of the Warmage: Heal, Bite, Shield and Brainstorm make it impossible to make this item fair early, yet have the power to be a second helm replacement. The line between "too good" early on and "as good as 2 helms later" is impossible, so I fear the item will never have a place.
Sabatons: These are pretty much unbreakable boots jr. I can't see a way to make changes without doing something radical to change their place without making them a primary starting item choice. (which is not what they are now)
Gloves: Will always probably be for the rich without a large paradigm shift in their use. Basically, you have more money, so can afford the same amount of life as your opponent AND more AA power. (which may or may not be better than stacking more life). Messing with armor / AA cost ratios with life is pretty hard to do and will be a drastic change in the way demigod plays.... so this should be right out the window as a possible change.
Useless Consumables. You cant waste money on consumables and get basic items while maintaining cit upgrades at the pace of normal warrank. This would change the game drastically and is also something that should not be trifled with. eg: Since most of the remaining items are for fighting demigods, they'd have to be as good a value as sigils. That is a problem since sigils are mostly about not dying. Offensive consumable items that kill as equally as sigils save lives is a can of worms you do not want to open.