Overview
Franco is a very fun to to play roamer. His role is Tank/Support. I don't find him very tanky but he can be tanky with proper tank build.
Strengths
I suggest you guys to play him as a support not as a proper frontline. His hook is very useful if you know how to use it well. The timing of his ult and hook matters a lot and you need to know whom to target aswell. Targetting squishy heroes is important but sometimes there are times when tanky heroes can be targeted too. While ganking lanes try to hide in the bush and ambush them with you hooks or your ult if they come too close which will be an easy kill for your teammates.
Weaknesses
His only weakness is his single targeted skills. He isn't very effective in team fights if enemies are tanky also he can't take alot of damage so you need to be careful about when to pick franco.
Best
This is the build that I use.
Support
This emblem setup helps franco with low cooldown, fast hp recover and fast roaming.
Tanky
You can use this emblem if you want tanky franco.
Battle Spell
Flicker is the most suitable spell for franco because you can do various things as flicker ult and hook then flicker into your teammates.
Early to mid
Franco is really usefull in early to mid because this is the phase that can shape the game. Your well executed hooks or ultimate can help you and your team to win a game.
Best With Cyclops
Anything that can burst enemies is really compatible with franco.
Watch Out For Khufra
Khufra is annoying