These reasons have been given alot for liking or not liking a girl (and really should be same for boys)
when it comes to diet I think most people can work around it, don't cook it at home, eat out if you wish to eat it, and I'm guessing not to come home and say "wow that chicken tikka was great"
as far as age goes, its harder to say what is the right age, depends on the person, I at 21 thought I was super mature reasoning being I was "running" the house while my father was away working, I was part of every decision they made, and could make my own decisions about household matter that where accepted, thats quiet a lot of for a 21 year old, But now 6 years later I am totally a different person, and the 21 one year back then i see as being much more immature that I thought I was, I'm sure by the time I'm 35 I will view myself as the 27 year old I am as again immature. So it depends on the person and what they have experienced in their life to their immaturity level, I must add maturity is not something you can gain fully, you spend your whole life developing it, at no point can someone say I've reached full maturity as I don't think there is such a thing...
But saying all this, its up to the girl at what age she wishes to marry, but waiting till you are older may give you a better understanding of yourself along with other thing resulting in a better marriage and relationship with your in laws.
Caste is a very hard topic to deal with, religion can be conflicting in this, and people feel very strongly about it. I do not wish to upset anyone on this point so I wont talk to much about it, and only say is maybe just maybe it is better to go into a family who has like minded views on the subject to avoid conflict, If you believe caste matters then try and find a family who believe the same, if you are open minded then find an open minded family. Beyond this it is hard to control who you fall in love with and at that point it doesn't matter since we are all equal.
Educations, Here I think most people understand now that both husband and wife should work, it better for the family to have 2 incomes then one. If a girl is a good match for your son or family but not educated or finishing I would hope the boys family is smart enough to watch or let her finish her studies after marriage it is at the end of the day a benefit for both girl and family. If the girl is not educated and does not wish to continue education then just see the girl, if shes good for your family and son then why say no at this point, after all in a few years she may change her mind or discover she can earn an income sitting at home doing something she loves. As long as you dont want to make it a status issue as in "look we got our son married to a Doctor" then this in my mind is really not an issue...
quickly adding that saying a girl will not look after guests is funny...Yash's mum has a good sense of humor :P
So what do you all think, sorry its kinda of a long post. are these reasons enough or should you say no to a girl for a real reason like she is a mass murderer or a puppy kicker..
:D