1) American Eagle LGA will now be served by Republic, Envoy, Air Wisconsin, and Trans States
2) Envoy returns to LGA at a much smaller scale to serve smaller mid-size markets with ERD and CR7 flying as YX 175's are shifted to larger markets.
3) With the announcement of E90 retirement from mainline AA that meant a "what now?" situtation when it came to American Shuttle flying out of LGA
American Shuttle effective 11/14/16 will be a mix of mainline of 319, remaining E90, and YX 175. Which from an F and mainline perspective the 175 and the 319 have an overall better comfort and service perspective. The 175's have 12 First, 20MCE, 44 Y.
4) YX 170's as expected are coming out of retirement and are currently in the paint shop/refurbs etc: (One of the few E170 painted pre-retirement pictured below)

5) The return of the YX 170's allows for shift of the 175 to larger markets such as the new Eagle Shuttle LGA-BOS, BOS-DCA, LGA-DCA. Also adds more frequency to certain routes like LGA-YYZ. The 170's have 9F and 60Y (legacy US Express birds, so no true MCE).
Here is the modified American Eagle E170/175 departures for YX as of 11/14/16:
NOVEMBER 14, 2016 YX / American Eagle LGA Departures: 40 departures
LGA-ATL 2x daily / E75 (remaining 3x daily will be 319, E90)
9AM and 12PM LGA departure
LGA-BNA 1x daily / E70 (remaining 3x daily will ER4,ERD)
12PM departure
LGA-BOS 5x daily / E75
8AM, 12PM, 4PM, 6PM, 8PM departure
LGA-CMH 3x daily / E75 & E70 (remaining 2x daily will be CRJ, ERD/ER4)
6:30AM, 8:30AM, 8:30PM departure
LGA-CVG 3x daily / E70
10AM, 2:30PM, 8:30PM departure
LGA-DCA 8x daily / E75
7AM, 8AM, 9AM, 12PM, 2PM, 4PM, 5PM, 8PM departure
LGA-DTW 2x daily / E70 (remaining 3x daily will be CR7, ER4)
9:20AM, 7:20PM departure
LGA-ILM 1x daily / E70 (remaining 1x daily will be CRJ)
3:30PM departure
LGA-IND 3x daily / E70
9AM, 2:30PM, 8PM departure
LGA-JAX 2x daily / E70
11AM, 9PM departure
LGA-MCI 2x daily / E70
10AM, 9PM departure
LGA-MEM 2x daily / E70
11AM, 6PM departure
LGA-MSP 3x daily / E70
6:45AM, 12:25PM, 7:45PM departure
LGA-PIT 2x daily / E75, E70 (remaining 4x daily will be CRJ)
4PM, 8PM departure
LGA-YYZ 4x daily / E70 (remaining 1x daily will be ER4)
9AM, 2PM, 6PM, 8:30PM departure