Simon spammers are the absolute worst. The fact that they need to spam with this OP character only shows how much of noobs they are. They think they are good but they are not. Spamming doesn't make you good, it will only make you annoying. No one wants to fight against a spammer. Nerf him.

His SideB (cross) has very little priority and gets easily clanked even by simple jabs
NeutralB (axe) has more priority, but many attacks can still outprioritize it (especially the swordfighters' disjointed attacks)
DownB (holy water) hugs the ground and has transcendent priority, so projectiles will simply go through it

edit:
Also my boy G&W easily crouches under some of Simon's attacks (Cross, FAir and BAir that isn't angled downwards, FTilt, and FSmash up close) and even his grab

edit 2:
also his vertical recovery is kinda sucky, a good enough spike can make quick work of him (and my boy G&W can be pretty damn good at it, BAir -> FAir might aswell be his bread & butter)

Also always expect a cross at the start of a match and after respawns.

remember that sora can easily get past simon's stuff using just side-b thanks to less landing lag and higher priority

a lot of people who play simon are yucky B move persons. very fun character and kit though.