Agree. By adding a splitter/combiner pair around your finals, you simply get 3 dB more output power before you start to compress. You should also put your matching circuitry immediately before and after the amplifier (i.e. inside the splitter and combiner). That way, you transform your PA input/output impedances to 50 ohms, then go into simple 50 ohm input/output power splitter and combiner circuits.
You could use a 90-degree hybrid (@tony), or a wilkinson power divider/combiner. Both will work, one just gives you a phase shift and runs the amps in quadrature. Check out microwaves101.com for some good reading on splitter/combiner/coupler fundamentals.
You missed an important spec... gain. How much does you final stage need to do, and what are your devices capable of? If they can do it alone, then just use one part, for simplicity. If you need a +3dB to reach your goals, then add the complexity of a splitter/combiner architecture. Design one stage that will work from 50 ohms input to 50 ohms output (includes all matching), then design the splitter and combiner, and finally put them together.... IF you have to go that far!