I actually don't mind scraping it that much, and even enjoy the adversarial aspects of writing scrapers. but it makes a lot of high level functionality like filtered streams or historical search much less accessible; I'd probably never have learned a lot of network analysis stuff over the last decade or so if I'd had to to pay to access streaming data first. Also, I think it's going to be harder for academic researchers to get institutional approval to scrape adversarially, so it could put a dent in a lot of social science research by forcing people to chase grants instead of focusing on their code.