Upgrade is pretty easier now
That's a bold and misleading claim with not much to back it up. I wouldn't say that it's easier to upgrade now. There are pros and cons to both upgrade systems for why A is worse than B and vice versa. There's also a higher drop rate(not always the case, as sometimes it can be really shit) aka more upgrading attempts. The fail/break rate now is also extraordinarily high now when compared to what it was compared to Retail. I can guarantee you 90% of the players you see with plus 15 are buggers. I doubt as many players farmed back then due to just how unrewarding it was, spending hours and hours of your life span just to get nothing out of it. Most players were too busy trying to figure out how the game worked due to the language barrier to focus on going higher than plus 11. Maybe I'm wrong and that upgrade right now is much easier now, although it's completely based on luck, nothing to do with difficulty. The fail/break to success rate ratio definitely makes up for the higher drop rate, and since Adv stones give 1-3(not 2-3 like it was in retail) it makes up for the less severe upgrade level decrease from break. From what I can understand the white stones being a drop, and with the language barrier gone's probably the reason why you see so many more players with "high" upgrades. Although you also have to take into consideration that most players who still play DBO probably play this game quite frequently/cash a decent amount.
and + 8 was better too than in DBOG.. Did way more damage with +8 than now, and im not talking about turtle.. DW/Crane/Plasma and most important Poko did more damage too - i miss my +10 farming poko from HK... SOUL and STR nerf sux @ss! FOC is overpowered now -> bad desisions in my opion..
That has nothing to do with the upgrade system, that's strictly tied to the damage calculations.