Optimus Prime has the persona of Optimus Primal, Soundwave has the persona of Shockwave and Sentinel Prime has the persona of an arsehole.

But I don't hold that against TFA - it's a whole different universe and these are entirely different characters. I have reasons for liking and disliking certain characters in the show, but it's got little to do with G1.
Btw Caine, the "G1 fanboys" you're referring to are often called "GeeWunners" rather than actual G1 fans. Almost all Transformer fans are fans of G1, but some are fans of GeeWun.
There's a fine difference between being a fan of G1 and fan of GeeWun. GeeWunners tend to be quite ignorant of anything that Transformers produced after 1987 and thus have a prejudiced view towards non-G1 mediums fueled by said ignorance.
The following is an excerpt from Transformers Wikia...
"GEEWUN is a snarky fan term for people who seem to have knee-jerk negative reactions to, and continuing difficulty in tolerating any of the post-Generation 1 (aka "G1") incarnations of the Transformers property."I first encountered GeeWunners
during G1 - before the name "G1" was ever even thought about. During the later years of G1 (post 1987) I often encountered other kids who thought that it was strange that I still liked Transformers and considered the first three years of G1 (1984-87) to be the best years of G1 and consequently see everything from after that in a very negative light - often born from ignorance. GeeWunners also have an ignorant dislike for G2.
GeeWunners really became a lot more vocal/noticeable when Beast Wars came out - though I'm sure that the existence of the internet would've exacerbated things. I'm sure many of us remember the amount of absolute hatred that GeeWunners had toward Beast Wars simply because it was different - they took objection to the fact that HasTak had "dared" to make Transformers into animals. It was during this heightened time of GeeWunn that gave birth to TRUKK NOT MUNKY. Year after year, GeeWunners kept complaining about all subsequent lines/incarnations of Transformers because nothing can ever be as good as early G1 in their eyes.
So really, we've seen GeeWunners running around for the last 20 odd years, being most particularly vocal for the past 11 years.
To be honest, I find that GeeWunners tend to be the most ignorant amongst Transfans - they often know very little about G1 despite being "avid lovers" of it. I find that most of their affection for G1 stems from warm-fuzzy nostalgia - GeeWunners are typically not "continual" (for lack of a better word) fans - i.e.: they're people who have stopped collecting Transformers for some time - usually a long time for several years, and have only more recently gotten back into TF collecting. Not all "born again" fans are GeeWunners (and I'm not trying to put down born agains here), but I find that the majority of GeeWunners are born-agains. I find that there are far less GeeWunners amongst 'continual' fans.
And there are different kinds of born again fans. Some have come to embrace other TF mediums, others haven't - and amongst those who haven't, you have different kinds again. You have those who simply say that they're just not interested in TFs outside of G1 - they don't necessarily have any opinions on non-G1 TFs, but they're just only interested in G1. The ones that tend to be labelled as GeeWunn fans though are the same, only that they
do have opinions - negative opinions - on non-G1 TFs.
But yeah - in short, you're talking "GeeWun" fans, not G1 fans per se.