Being accurate isn't less-fun, it just depends on what are your plans for the costume (contest, display, conventions, halloween, etc).
That design looks quite amazing anyway, and you'll feel very comfortable at the con as well, with less lights going off because of sweat, movement or people pushing you by accident . You could even make some rinzler moves! haha
Everyone has a different view of costuming and cosplay. I understand both points, yours and Megatron's, and I agree with your last point. Some people are into costuming for competition reasons, while others do it for fun.
While I costume for fun, I do like to try and be as accurate as I can, but sometimes I have to make changes for various reasons (money, materials, time, comfort). I know my first Rinzler costume wasn't 100% accurate (I wish it was). I know things are missing, but I'm still proud of what I did, and I had fun wearing it. In the end, that's all that matters: if YOU are proud of your work and if YOU enjoyed yourself.
Do it the way you want to. If that means being completely accurate, then kudos! I wish I could do that. If it's trying your best, then kudos as well. I'm there with you. If it's taking a design and altering it, then another kudos! I love seeing people's designs for both original and existing characters.
So no, accuracy doesn't mean 'less fun', but if you get too absorbed into being 100% perfect... you could just end up being miserable. Hope that made sense.
And as for the last part, I know what you mean about people running into you. I got a few rips in my Rinzler costume (mostly on the shoulders) from people running into me. And your last point is another reason why I'm excited for this version. My first costume has a lot of delicate wiring on the inside, so I couldn't pose very well. I was really looking forward to doing his poses too because I had practiced. I'm very flexible, thanks to gymnastics, so I can do a few of his moves. With this new version I plan to use reflective tape so I can move. I'd like to have lights, but if I can't pose myself properly, then I'll go with the tape.
Whoa, sorry for the novel, guys. lol