I have no idea what shade does, if it is good, then get it instead of ping.
My vote is to sell rapier and then purchase the following, in order:
Data Blast, Lockpick mk.II, Ping, Oracle.
Data blast is super-good, that is a five-tile RADIUS, so eleven tile diameter, that is generally more than one thing, so you are getting the same value as lockpick2, and is sometimes half-a-dozen things, which is pretty much the best power efficiency that you will get without a timer. The problems are that it only affects visible targets, so you can miss things if you hack as you explore, it is inefficient for solitary targets, or targets that become solitary because you blasted all their friends, and you can hack things that you didn't want to, such as daemons, daemon fodder(I would reserve my praise because it didn't give us a daemon remover, and we needed to come to a server-farm in the first place...), drones, and turrets... It is first because it is obvious that it is selected and should be the first resort and can require some spamming.
Lockpick 2 is just simple and reliable. Dagger or Rapier would work instead, rapier being better on the first alarm(and cheaper because we already have it) and dagger being better occasionally, but lockpick+'s consistency wins the title for me. Somewhat redundant with data blast, but good for those 10-strength firewalls and clearing out a null drone, or a solitary camera that is blocking exploration. Second because to keep your general hacks together.
Ping is there to give a non-agent method of guard removal. If you get lucky you can send a guard to the far-side of a wall and take them out for a few turns that way. The timer is a pain but usually doesn't come up and you can do the same thing with agents, but that is risky or time-consuming, and it only works on sound-sensitives, and may also trigger sound bugs, I am not sure on that point. But a just plain handy long-range option for (de)synchronising patrol patterns or luring a guard away. Third to keep it visible because it is easy to forget as it is highly situational. Shade would be an alternative if that is good but you don't want to spend too many of your five slots on guard programs...
Oracle is really nice. At this point, you are generally getting 2 firewalls for 2 power, but that can change. Daemons on cameras are rare, but that can be a risk. But mostly it is a fantastic method of exploration, especially with seed to pay for it. It only hacks available cameras, so you need to wait until they are turned on for the full effect, but being able to hack something, especially a camera, without getting vision on it, is nice, and four is a manageable cost. Cameras are generally cheap, but their costs can go up and a three-strength firewall for four power would be a bargain... Also, cameras tend to be difficult to hit with E.M.P. weapons... Last slot because it is a big deal early but largely irrelevant late, so you can afford to forget it when that is a risk. Oracle is largely a bonus, leave it behind and there may be some small chance of being able to afford the volt disruptor, or some half-decent agents...