Altough your post is old, i have all answer to your questions.

1. The contractor is giving a good service.
2. There is an issue with 2003 and maybe some 2004 solenoids.
3. There is new solenoid that have larger wires so i find them easy to recognize. They seem to perform good.

4. i disagree that weathermatic products are bad. I installed some valves in 1991, 1992, 1993, maybe 1994 and all valves still remain working without any failure. Ok a second time : WEATHERMATIC VALVES ARE WORKING WITHOUT ANY FAILURE FOR 12 TO 15 YEARS.

5. Almost every irrigation companies i know had batch problem one day...

Hope it answer all your questions. I think I've installed about 6000-7000 weathermatic valves plus the same quantity of another brand and tried all major brands.