To play devils advocate here, you look at a Leve like Dunes or ACU and with a 4 way link you can maybe get between 10 and 20k SP depending on how lucky you are. Then you look at another BW leve, say A Devilet's Best Friend where a 4 way link will be lucky to net you 2-3k SP, same with Whipping The Curs or A Terrible Thirst. In fact, once I reached a level that I could do level 40 leves and I saw some of the ones on offer it made me wonder how SE could say soloing is a viable option.

Think about it, you are level 40, I think it's 77k to level 41 then (give or take). You go to the counter and get Curs, ACU and Dunes. You can probably solo Curs on one star, maybe two for 2k SP. You realistically can't do Dunes due to the regen on Hounds, but that would give you the most SP so you try, and probably lose 9 mins of the leve through weakness. OK, time for ACU but most of your time is then spent dodging and/or clearing mites to get to the Dodos.

A better correlation needs to be made between SP rewards over all leves versus SP limits between levelling as well as addressing the problem of losing leves due to timeouts / dc's as well as addressing the chance of success in a level for parties of 1-2 people. Of course people are going to fail leves to give themselves a better chance at levelling, it's 100k between 49-50 and the level cap can potentially get to 100 in the dats.

If you think failing is cheating then don't do it. As mentioned when a level is failed there is no reward.