It is possible to publish a SID that meets the twin engine FAR 25 minimum S/E performance gradients over an assumed range of conditions
That procedure would be so restrictive, with the combination worst case factors, it would be unusable. The chart would have so many caveats, you would need 3 pages to publish the chart.
The RNP-AR EO DEP designs have every single factor added. Worst engine in the fleet or class, all the bleeds on, icing on, engine wear/dirt, every drag factor possible on the engine and ac, and MTOW. The result is that many times, you have double digit climb rates, especially when you get up around 30 or 35 C. Add a 737-700 to the fleet with 20K engines and see where it all goes.