I understand the point you are making. How this online virtual world will work is to address how K-12 education sorts students and the transition to online education in schools to address budget cutbacks.
First, students are sorted in K-12 by age rather than by interest and ability like it is done in college. Secondly, schools are putting 60+ students in a single room, call it a "computer lab" to get around class size restrictions and rather than staffing the lab with a teacher, they use a "facilitator" who takes attendance, solves computer issues, and hands out/collects assignments & tests, at a fraction of the cost of a qualified teacher.
The model I envision has students in that large room log into classes they are interested and proficient in. Thus, each student in that lab will be in different classes with students of all ages sorted by interest and ability.
I also want to stay away from texting as many students are not proficient at communicating with words. They are visual learners. There are those (like me) that can read a book over and over and the words don't "click" in our heads. But if you SHOW us, we get it right away. That is the reason for the visual Second Life classroom over just a text-based classroom.