There's no set criteria, it's just a personal thing what people decide to give. Like the previous comment says, you will never get 5/5 because anyone could give you any rating for whatever reason they choose. Newgrounds is one of the last remaining media creation sites that is completely human driven, with no algorithm, so 5/5 is all but impossible.
Watermarks are a good way to protect your work so you shouldn't stop doing it just because you don't get 5/5. Your watermarks aren't obnoxious and don't detract from your work. You are trying to protect your IP, which is perfectly understandable and if someone marks you down for it, well like the other commentor says don't take it personally.
I've been on NG since 2006, trust me when I say your art is getting views, favorites and high ratings so you are doing well! I'd say views, being frontpaged and any awards/recognition matters more than ratings anyway, so keep promoting your stuff and getting your name out there!
Keep up the good work 😀
SouSTAR
It is not possible to have 5.00/5.00 on a anything really, there will be always someone who will rate in half a star or something
Don't put take these ratings too personally. People tastes vary, some don't want to see watermarks, some don't mind it (which seem to be the majority) so really, it's nothing :)
But yeah, rating less because of a watermark, unless it cover and practically cover the whole drawing, is a bit... Yeah
Your art is beautiful btw! :D
SupNovaGY
Yeah it just felt a bit unfair due to the fact I’ve had art thieves in the past especially from Reddit stealing my works and claiming they made it…
I do also wonder if the rating system is affected if an artist uses glaze or nightshade too? It leaves a filter that the human eye can see but isn’t that bad though it is bad for the AI lmao
Also thank you so much, I’m happy you hear you still like despite the watermarks 😭💜