Yep...the regionals are feeling a pilot shortage. Simply put, it's hard to find a large number of college graduates willing to work for $20-$40,000/year in any field.

The bonuses help entice a pilot who already wants to work for a regional to come work for yours instead of a competitor. However, it'll take overall wage hikes for year 3+ before good pilots who had to go find other higher paying employment to support their families decide to come back. If the bonus brings pay up to about what you make now for 2 years, then in year 3 the pay goes back in the toilet, you aren't going to leave your non-flying job to come to a regional.

There are plenty of pilots out there. One of my instructors about 4 years ago left the regionals to go back to instructing because he made significantly more as a full time CFI. Make pay competitive with other industries that require a college education (whether you have one or not, you paid for one), and you will staff your flying no problem.