i really loled, if you seriously think people accept members based on them having NIN. You have another thing coming. I'd rather pickup a talented player that plays a DD job and wait on a NIN, than pickup a NIN and pass on a DRG only. If you seriously would have passed on an Audino, or either Eles because they have/had DRG only you would be foolish. end of story.
If a player is talented enough and excels at a job(puts most effort into said job) then the person should be able to go that job. I'll tell you right now, that i've seen plenty of people half ass lvl NIN because they have the same mentality that you do. I'd say save a linkshell the time/effort and just concentrate on the job that you excel at. Your mentality states that a person should lvl a second or a third job just because the linkshell may "benefit" from it, I'd rather have the person that has very good gear I.E. the well equipped DD only.
Let me ask you a question, if your linkshell had 2 applicants apply at the same time with 1 slot which would you choose. The generic DD w/ NIN lvled to 75, or a well geared DD w/ full homam etc etc. In respect to your comment earlier, there is no set parameters on what jobs you need. So you can accept any job.
I pity people that think a well geared DD doesn't take priority over a halfassed DD with a mediocre Tank job lvled.