It is true that some of the benefits are below average; capping PTO at 20 days for all employees is a sad amount compared to other agencies and insurance carriers, who give that amount to first year employees.
After Arthur J Gallagher acquired William Gallagher in 2016, turnover was quite high for 2 years, but seems to be decreasing to almost normal levels. The office is still understaffed, but has many positions open, which will hopefully be filled soon.
Managers are stretched thin, because it is a Gallagher standard for them to also have "books of business" and bring in/contribute to revenue. This likely perpetuates some of the problems.