I know it's convenient…but it completely collapses the endgame into easy mode.
Slap a portal down near a boss? Done….you basically already won.
Exploring the wilds? You'll never lose your shit again because you can slap a portal where you dock and come back…meaning taking risks and being dumb isnt punished….which then makes all endgame content obscenely trivial.
Imo, portals should be treated like a flag to be destroyed by AI. A portal being put down should summon waves of AI that want to destroy it unless you develop the area around it to defend it.
As it stands…the pocket portal phenomenon robs the game of any complexity or risk. There needs to be punishment for just slapping a portal down anywhere to easily revive yourself…you should need to invest in a place for a portal or there needs to mechanisms that make portals difficult to set up.
Ideas:
Either through aggressive AI OR portals need to be around an amount of infrastructure that can't simply be kept in your pocket.
Portals need an item that is dangerous…such as an ember stone that burns the user and will destroy objects it is stored in…meaning you can't just slap it into your boat.
So making a portal requires getting a stone to activate it nearby or establishing safe zones to heal along the way…etc.
Source: https://www.reddit.com/r/valheim/comments/pdy8sf/unpopular_opinion_portals_specifically_pocket/