First of all Dilshan is ten times better then Mubarak and Wijekoon. Why compare other batting options to Mubarak, when he clearly is not good enough to play Test Cricket. He can score million runs against Bangleadesh A and take million wickets, but he still wont be good enough.
If pace is all that thats required then why don't we just play Mirando, Dihara and Malinga and forget about Vaas. You don't take wicket cus you can bowl mid 140s, if he bowled in the 150s then maybe we should consider him on the back of his pace. But really is he that fast in comparsion to the rest of world.
Zoysa and Chandana - well there are spinners who are bowling better then Chandana, Hearth, Weerakoon and Bandara are all bowling better then him. But he is back in the Sri Lanka A OD side, so he preforms his a good chance to make the ODI side. For Zoysa, last i heard he was injured, but if he isn't his batting isn't good enough to bat at seven, he is way too inconsistent. When it comes to his bowling, yes he maybe better then the guys currently there, but how many times do you have to go back to the same guys over and over again. Prasad, Maharoof and Malinga are preforming at domestic level and if given a decent run at international level, may convert those preformances to international cricket.