The nerfs to solo dojo were completely unnecessary imo. Increasing the points from Papulatus and Mu Gong would have been enough, and it wouldn't affect solo play anyway since they're impossible to beat solo. Now soloing the dojo is way too slow, which is disappointing since not everyone will be able to find parties to do it with.
What is the current numbers? If it's 1 point for the first 5 stages instead of 2 points for both solo and party then that is rather fair, assuming solo player is giving up on the Manon stage. You can't just increase the incentive to party without making solo a whole less effective. If solo is only about ~20% less effective than being in a party people will still solo Dojo in the end of the days. Players tend to choose solo over partying if partying is not rewarding enough. It can't be helped as that is how you increase the incentive to party play especially for today's "MMORPG players" when the majority of the players are trying to bring less and less people each day to lessen the hassle to gather a group of party and/or maximising profits among themselves. MapleRoyals is a nostalgic server and I suppose the "teamwork" was one of the attracting side which made us join this server instead of continuing on the current GMS where it is pretty much a single player game with internet connection. I'm rather happy of this change and hope to see more parties instead.
Compared to before the patch, solo Dojo players get 19 less points for completing up to Manon. That's a notable difference, and it gives players who ran dojo before the patch a pretty big advantage over players who have yet to run it. It also makes it a lot more difficult for lower level players to get points, party or not. It's not like solo Dojo was broken or anything, the rate at which players got points was perfectly fine. They should have just increased the points from party Dojo without touching solo.
Necessary change is needed when the situation calls. There is a lot of changes made in the past that eliminated the advantages of players prior to the changes -- summon farming being one of the biggest changes. What have been done is done and it should not be used as a petty excuse to revert back to how it was just because you couldn't took advantage of it. It is still plausible to get white belt solo or with a party depends on what class are you playing. And this shouldn't even be an issue when the majority of the low level players are HP washing where they don't even have the necessary strength to beat Mano. Those who need to farm tons of points for the endgame belts should be at the endgame level when attempting anything similar to this where it involves untradeables, just like how zakum, HT, MoN work. I guess someone can actually take advantage of this and start a VIP service to carry someone who is HP washing heavily to get a belt in order to get more base Int. Indeed you are correct that solo Dojo was not broken until it comes to increasing the incentive to party where I've already explained above.
