Your situation parallels my own recent visit in many ways. We stayed for 3 cold, wet and stormy days at the end of a tiring trip and were very very impressed. However we also will stay elsewhere next time.
A few comments. There were internet terminals by the phones off the main lobby. Though you may have meant in room access.
We raided the nearby Ikspiari mall via the monorail every night and came back with cheap dinner and breakfast. Next time we might stay at the Ambassador to be closer to it.
Didn't really feel the lack of public spaces. Our room was just so comfy. However I understand your point. Mira Costa is very much a hotel rather than a resort hotel (if that distinction makes sense to anyone). Which was what I was expecting I guess so I wasn't disappointed.
The thing that really made it worthwhile to us was the early entrance into the park. We were 3rd and 4th in the park one day.