What kinds of things from reddit would you like to see Lemmy avoid as the user base grows?
Personally I think not having karma limits is nice currently! I understand why they were used but grinding karma as a lurker on reddit was frustrating.
It's not about making the user leave, because of they know they are banned they'll try to evade. Shadow banning gives the desired effect while not tipping off the user. So they post away, to nobody.
The original use case for Shadow banning was bots I think. To them it looks like they're comments are still being posted, but everyone else it's invisible.
IP banning is such an annoyance if you are unlucky enough to only be able to deal with ISPs that do not use fixed IP addresses.
"Can't post today, because another random person got my IP 'du jour' banned in the past" is a pretty terrible user experience.
And the pro troll uses Tor or a VPN and only needs to reconnect his client to receive a fresh IP address. I consider IP banning to be a very mediocre tool at best.