Galio has a few issues:
1. Although he counters AP mids hard, AD mids can stomp him (situational pick)
2. Huge mana costs
3. Even if you would play him succesfully, you would either be full tank or AP tank, but never full AP.
4. His ultimate is great, but you need to be in the middle of the enemy team in order to use it optimal, which means using flash as a suprise initiate. (flash dependant)
5. AD teams overal are more popular than AP teams. Galio only gets stronger by MR, not by Armor, meaning that you will not be that amazing damaging tank in an enemy AD composition.
These were the main things I could think of
Overal, if he WOULD be against a heavy AP team, he might be a legit pick. Other than that, his high mana costs and ult+flash dependance make him very unacttractive.
Since "capable of being done" is a broad concept, I'd say yes, he is viable. However, like Throatslashers tier list shows us, he is still one of the worse mid-laners, so it is not really recommended for ranked play unless you are absolutely sure what you are doing.
1. Although he counters AP mids hard, AD mids can stomp him (situational pick)
2. Huge mana costs
3. Even if you would play him succesfully, you would either be full tank or AP tank, but never full AP.
4. His ultimate is great, but you need to be in the middle of the enemy team in order to use it optimal, which means using flash as a suprise initiate. (flash dependant)
5. AD teams overal are more popular than AP teams. Galio only gets stronger by MR, not by Armor, meaning that you will not be that amazing damaging tank in an enemy AD composition.
These were the main things I could think of
Overal, if he WOULD be against a heavy AP team, he might be a legit pick. Other than that, his high mana costs and ult+flash dependance make him very unacttractive.
Well, if your definition of viable is:
"capable of being done with means at hand and circumstances as they are"
(http://www.urbandictionary.com/define.php?term=viable)
Since "capable of being done" is a broad concept, I'd say yes, he is viable. However, like Throatslashers tier list shows us, he is still one of the worse mid-laners, so it is not really recommended for ranked play unless you are absolutely sure what you are doing.
Click here for more information