I haven't seen it mentioned before so sorry if it's been brought up! Honestly I would love to see it implemented where you can upgrade the portal like you would the work bench or the forge, to allow for teleporting various ores/items. It would allow for the current natural progression and working up to the next tier without completely eliminating the need for boats and exploration.
You still have a challenge of gathering the right items or unlocking the upgrades past various boss threshholds. Might even be cool and incentivise fighting the bosses multiple times if you made their trophies a component required in the portal upgrades (ie fishing bait).
It also makes it less likely you will have an abundance of upgraded portals, while still having it available as an option for those who want it.
Could still not work but I would love to see it as a middle ground between current restrictions and just completely removing them!
Source: https://www.reddit.com/r/valheim/comments/10f83va/portal_upgrades_yay_or_nay/
