When gemming explorations, respawn timers should be instant (but only if the entire battle is gemmed, so you can't just gem the last minute of it to take advantage). Or, we should at least be given the option to gem the respawn timer itself, with an indicator of how long until the monsters reappear. Since fighting weak monsters is the only reliable way to get common items (even the cheapest gem chest gives more rare materials than common), and we need over 400 for each LP, respawn timers are a major hurdle when trying to farm those pesky gunpowders and irons. Every time we gem our sail time, we still have to wait 5 minutes for the monster to respawn :c If we got 2 iron from every time we fought the crab, and gemmed 100% of the exploration process, it would still take over 1000 minutes just waiting around for the crab to respawn. With the drop rate being lower than that, even if you spent an entire day doing nothing but gemming the crab (which would take thousands of gems in the process) and waiting for it to respawn, you'd be lucky to get half of what you need. And thats for only one LP. Doing nothing but sitting there, gemming the exploration, waiting 5 minutes, and repeating, all day. This isn't a complaint about the drop rate or anything, it drops plenty often enough. Its about the downtime and infeasibility of farming it, even when willing to spend the money and time to do it.
I like the idea of. Gemming a respawn. Especially with certain legends using up tons of materials gemming a sail is a good option. Gemming he respawn afterwards would make the action of actively farming the map easier. Think it might be a bit complex to program this into the maps though...
