Let’s get this straight, considering equall skill for all players, 2 decent heroes will always be better than a ChoGall, even if he has his perks. Still, practice makes perfect, and even if at first i sucked with this hero, who according to hotslogs has a 44% win rate, now, while playing Cho, and with a decent Gall partner, i manage to get 70-80% win rate 😛
See here what i mean:
Now, to explain the skill choices:
I always pick the ones who augument „consuming blaze” (W), as you really need all the protection and healing you can get, and many fights will be melee, „rollback”, to make the bomb come back to you and better clear waves, plus get some funny kills, „upheavel” is the only ulti you need, as it can disrupt enemy casters, prevent enemies from escaping or just pull them near your towers or to a more favorable teamfight spot. I always get invulnerability („molten block”) as you will need it, and „favor of the old gods” because when you pull enemies towards you, you will need to fight and 50% damage reduction for 5 seconds is the best thing you can hope for.
For Gall, the most important skills to get are „bomb’s away” (bomb range) and „dark descent” (bomb damage). Although „twisting netter” works in some cases, i preffer „shadow bolt volley”, as it fits better with my skill choices.