Especially if someone is looking for a raise. At least where I've work, the more senior engineers (i.e. the ones who have demonstrated that they should get higher pay) are the ones who are constantly evaluating new ideas and new architectures, reviewing other peoples code (in open-source, these people are committers, not just contributors), collaborating with other projects that integrate with ours, etc.

I get the point about everything being 100% new at a new job being more uncomfortable than the incremental newness you should constantly be experiencing. But still - if you do have a hard time justifying a raise, remember that you're asking the company to bet more money on your. Bet on yourself first, step outside your comfort zone a little, and try lead in a way you haven't much before.