There are many smart people here - you will feel dumb or outclassed at times. Track to promotions can be difficult because of the talent.
Workday seems to provide a modicum of autonomy across different geographic areas. Different geographies have different ideas on how to achieve goals while maintaining Workday's guidelines.
Yes there does seem to be some cliquishness between the old guard and the newer folks - this is understandable because they've worked together so long, have become friends, and had to struggle when the company was much weaker competitively. Some older tenured employees do seem to be riding the gravy train at times. In this day and age, you can't just ride tenure. You have to back it up with performance. Your tenure may buy you a little respect initially but if you can't back it up, you'll lose it quickly and then some. Any interactions I've had with older guard have been neutral or positive. Forming meaningful relationships takes time but there is always an underlying level of respect. It is hard to get hired here, afterall.
Workday has been scaling tremendously and with that comes growing pains and more layers of management. I believe this is necessary, however. It simply does not make sense to have 1 manager oversee 50 employees. The structure is broken down so that individual managers help 5-10 people and can give attention to their reports. Due to growth, some got promoted to managers while others didn't. Missing out on that promotion can be a source of frustration which is understandable. Again, tenure should not be the sole metric of promotion. Performance matters.
Like any organization big or small, there's politics. If you're naive enough to believe any company, organization, or even church doesn't have its own internal politics, I've got some oceanfront property in Arizona to sell you.