Avaya is following in the footsteps of its former competitors. The competitive technology outpaced the development of the "old world" leadership. Avaya will still be around 10 years from now, it may not be called Avaya, but there will still be many clients using those premised based legacy solutions, buying support and upgrades to run there businesses.
You really have to look deep inside yourself and ask the question, do you want to work for a company that charges you a fee to participate in its 401K program? If in sales, do you want to be in a position where your commissions are optionally paid based on the whims of someone in finance or the compensation team?
For the older legacy Avaya employees, you will land on your feet, just put feelers out there. If you are trying to get just one or two more years, you should be okay. If you are a newer employee, keep your eyes open for new opportunities.