TL;DR
No need to worry: when you write a good story, any name sounds great.
Good names are as good as the story
Good unique names are not easy. In particular, it is not easy to come up with a good fitting name before having the whole story laid out. On the other hand, most of names however sound great not because of the name itself but because of the character bearing it.
To give an example, <PERSON> is a very simple name. It could have been <PERSON>, or <PERSON>. Even <PERSON>. It sounds great and unique because <PERSON>'s story resonates with the reader.
Get to know your character, you'll love the name
If you start writing your story, it is quite possible that at the hundredth iteration of spelling out "<PERSON>" you may find that such name was befitting of the character after all. 873
In fact, over time you have become acquainted with him, and Mr.<PERSON> is not anymore just two silly sounding words put together, but a character with a past, a story ahead, goals, desires, conflicts, and all that makes him interesting.
<PERSON> is equally a good name. The choice of less common words often makes it easier to jump start with a positive attitude towards a character. The feeling of such name being pretentious is actually more a feedback about the story than about the name. In other words, the story may be duller than expected and <PERSON> is not living up to the expectations: raise the stakes, increase tension, add conflict.
A note on naming systems
Given the above, having a naming system can save time. A naming system is a set of rules that can help you quickly generate names that look and sound from the same place.
For instance, you could stick to the first- and family-name naming convention, and use colors as the first name, and a combination of tree names and tools for last names: Red Birchsaw, Blue Oakhammer, <PERSON>, etc...
As an anecdote, I recently came across two animes: in the first the characters from the alien world had names of cocktails (princess Pina Co Lada, knight <PERSON>, <PERSON>, etc...); in the second, one character had to name a clan of goblins and went for Gob-something (Goba, <PERSON>, <PERSON>, etc...). These are obviously silly names per se, but in the context they quickly stick to the characters and it becomes natural to hear/read them without laughing. 873