I absolutely agree that having a 'feel' for the game and having played it for a while is absolutely crucial in being able to create for it.
However, I have to disagree with your last point in that post - I don't think it's necessary to slavishly follow official wording conventions. For example, as someone with experience in both designing and playing the game, I do use 'roll the D20' in my powers, not out of lack of experience, but because it is equally clear (at least to everyone I play with - what 'the D20' is is fairly obvious) and is more concise than 'the twenty-sided die' - it's quicker to say, takes up less space and reduces word count at no cost of clarity. Equally, I'd say the same about constructions such as 'if you roll a 17+' over 'if you roll a 17 or higher', 'Valiant figure' over 'figure with a Valiant personality' etc..
Not only that, but official wording was notoriously inconsistent in how it said specific things, often doing it one way on one card and another on a different card, and they themselves refined their wording over time. If you look back at Water Clone now without context you'd swear it was a power from a custom, not an official card, and Johnny 'Shotgun' Sullivan's 'only needs a clear sight shot' became confusing when they finally defined what clear sight is, as a discussion in The Varja's book showed.
C3G has taken on a more specific, regimented style, but even then, I don't feel differing from official (or 'official', in the case of C3G precedent) wording necessarily indicates a lack of experience if done mindfully - at times it can, particularly when the power seems to be written in a way that shows no similarities to the usual structure, but making conscious changes for the sake of clarity, brevity or a particular goal I feel shows the opposite.
I'm particularly thinking of the changes to wording @
NecroBlade set out that he'd be using in
his latest customs thread - while I have no plans to use his units as yet, and don't plan to incorporate all his wording changes, it's hard to argue with his logic on any of them, or say that they weren't thought out decisions made based on experience.