Whoever is arguing about having a great game, but being unable to make decent graphics, here is my advice.
Make the graphics anyway. Sometimes badly drawn graphics do a game 100x better than graphics that look good on the surface, but players will immediately recognize them coming from another game. If the graphics take too long, just do them with a limited palette or in NES style. (if they still take too long, you are either not dedicated enough, or your game is too big. The good news is that it's always either one of these reasons.)
The high majority of games with graphics people recognize as stolen will be overlooked as "too amateur to waste my time playing", while some of the greatest, most recognized indie games are done so because they have graphics their five year old sister could have made. You are right in saying that graphics are just substance. They do make the first impression, and if you are an amateur, then you shouldn't be afraid of that being your first impression. The point is that if you want your first impression to be that of a creative game developer (as opposed to an uncreative one), then you simply have to have graphics that give some indication of something "created". Something someone else created years ago just doesn't cut it.
I'm not really sure that this really has to do with the graphics. Let's be honest, you can sort of tell whether a game is "too amateur" based on the overall presentation, regardless of whether they used rips or not. For those who allow the chipset palletes in rm2k3 limit the way they present their graphics, it's obvious because it will result in crappy map design. Clearly, if their hero is a Crono charset with a japanese-style name, and the chip sets are a mix of rtp, sd3, and zelda, it's likely that the overall presentation is going to be crap.. and if the presentation is crap, rest assured their storyline, gameplay, etc. will be just as jumbled, or amateur. In that way, I don't respect those who used character sets from games that have an emotional connotation to them... like crono, or link, etc. in a different context.
I think people should be a little more mindful of where their graphics are coming from. I don't appreciate homemade graphics if they're so poorly done that it affects the quality of the game. You're right, the high majority of games with stolen graphics come across as amateur, but this has more to do with the creators in the community than being a manifestation of the graphics. Naufragar was a popular game that used rips, but because the creator spent time into the overall quality of the game, it didn't deter people from playing it. that's just one example. The most popular games (legion saga, ara fell, hero's realm, sacred earth: bonds, balmung cycle, and the list goes on) used graphics that are known to people, yet become extremely popular in the indie gaming community.