Math: Perception of only or mostly doing research in Master's for Ph.D. admission folks Background: I'll be starting a 1.5 - 2 year master's program in mathematics this coming Fall in the US. Because of my non-degree graduate courses relevant to the program and my research interest, I can easily fulfill the requirements of this program within a year. However, my main goal is to gain and tangible research experience in preparation for a Ph.D program so I plan to remain in this program for 2 years. 

Question: Will my application to Ph.D programs and fellowships be diluted if admissions folks see that my second year in this Master's program consisted mostly of research with at most one class per semester? 

I want to reduce the course load as much as possible in order to give me time and flexibility to do research with the benefit of less tuition fees (if any). However, this all would be moot if such decision would raise red flags among admission committees.

Besides focusing more on research than classes, any other things I should look into while in this program?
Background: I am the director of graduate admissions in the pure math department of my university.

In my experience, we basically ignore "research" conducted by undergraduate and masters students (unless is it truly remarkable, in which case you will almost certainly not need advice on the internet to get into a strong PhD program).  It just isn't a good predictor of whether or not you will be successful in a PhD program.  You will get very different advice from people who are not mathematicians, but you should ignore it -- graduate programs in math are very different from graduate programs in the other sciences.  This advice also might not apply if you are applying to departments of applied mathematics.

What we care about are 


The courses you have taken, and
Your grades, and
Your letters of recommendation, and
Your GRE scores.


The above list is un-ordered; different members of the committee weight the above factors differently.