What steps will reproduce the problem?
1. Open up an executable to analyze and define two regvars in a function. Ex:
 a = eax
 b = ebx
2. Obtain the func_t object and call the regvars accessor.
What is the expected output? What do you see instead?
regvars should be an array of regvar_t elements, not just the first one.
What version of the product are you using? On what operating system?
Win 7 64bit, IDA 6.4.130702 Demo, IDAPython 1.5.5 
(idapython-1.5.5_ida6.3_py2.7_win32.zip)
Please provide any additional information below.
The included script should reproduce the problem.
Looking at the other fields in that struct, it looks like "regargs" might have 
the same issue.