I've played this game since closed beta phase 3. It took me from launch until January to get my first 50. I was 37 marauder before I joined a new, active Linkshell and learned about the broken leve system. I got from 37-50 in about two weeks just from doing leves every reset.

I got 50 Con, 50 Arc, 50 Glad and 50 Pug via the broken leve system. Yeah, some viewed it as cheating, but it was the only real way to decently rank up at the time. Parties outside of leves were horrible SP and not ideal at all. It could still take about 3 weeks to a month to get something to 50 via broken leves.

When they fixed the broken leve system and made partying a viable option to rank up, it became easier to rank up. It was still slow for some and took me about 2-3 weeks to go from 36 to 50 lancer on leves alone. Next, I worked on Thaum. I did more grind parties for that. To get from 48-50 was a solid 8 hours of grinding raptors in Coerthas.

I think the reason they added in EXP chains was to HELP people, not HINDER them or put the game in "Easy Mode." All classes benefit from other classes. You wouldn't want a Gladiator without any self-healing abilities or taunts/enmity generation from other classes, would you? Not ideally. Most people refused to rank up other classes because it used to be so difficult and time consuming to do so. Now that they've made it easier and faster, more people can rank up other classes to better round out their characters.

Also, this helps new players and existing ones who don't have a 50 class yet. If it's easier for them to get 50, they'll be able to do more content and play with their friends who are already 50.