This time of year, many people reflect on what has happened as a way of figuring our what may happen in the future. Looking at world affairs, it seems 9/11 may be a good place to start.
Qaddafi, Hussein, and bin Laden have been killed in the years since 9/11 yet much remains unchanged. Al Qaeda remains the terrorist boogeyman and the Middle East is perhaps less stabilized than before the beginning of the war on terror. Mubarak's ouster has had a more dramatic impact with the ascendancy of the Muslim Brotherhood (which was outlawed by Mubarak's predecessor, Anwar Sadat).
In Obama's second term, Kerry will replace Clinton at State, Hagel has been nominated for Defense and Brennan will take over at the Central Intelligence Agency. Kerry is not seen as doing anything to lessen use military presence overseas. Hagel is seen as anti-Israel and Brennan is seen as major proponent of drones. The three combined means tensions in the Middle East are unlikely to be decreased and more remote targeting of "terrorists" will be conducted via airborne robots. (Hagel should get confirmed but pro-Israeli groups and politicians may lobby to block his confirmation.)
All of this continues to ignore our neighbors to the South. A long time, I heard a South American analyst lecture about Colombia. His conclusion was that the perceived exploitation of Central and South America by the US was the reason for the drug cartels success. Basically drugs were being produced by with the intent of destroying the US from within (this was back in 1988).
Back in the 1980s and early 1990s, cocaine was the main drug the Colombian/South American drug cartels smuggled into the US. At some point in the mid-90s, the cartels realized the market for cocaine was pretty much maxed-out, no room for increasing the market with new users. Thus was born the higher grade heroin that we see today. Heroin with a higher concentration could be snorted or smoked so cocaine users would be attracted to the new heroin (and not appear to be a junkie shooting up in an alley). Unfortunately for these new users, they discovered the real strategy of the cartels was to get users hooked. Heroin is immediately addictive unlike cocaine.
Heroin is produced from poppies which aren't grown in Colombia so a new partnership was formed between South American cartels and Afghani poppy growers. The connection between cartels and Taliban leads many to speculate as to the real reason we are in Afghanistan. The new Secretary of State (Kerry) and Sec Def (Hagel most likely) will have to assess the consequences of keeping troops on the ground in that part of world.
China continues to build-up and improve its military capability which begs the question, why? Even if not for a direct confrontation with the US, Chinese technology will force the US to keep developing new weapon systems at a somewhat quicker rate than has happened in the past. Part of the reason the F-35 cost so much is its lengthy development time (plus coming up with three distinct variants to meet the needs of three different service components).
Speaking of the F-35, this is most likely the last manned fighter aircraft we will see. Drones and robots have advanced to the point that manned aircraft are actually a barrier. Flight characteristics are hampered by the need to keep the pilot from being squished to death in a high G-turn. Drones can now take-off, fly and return to base without human intervention. Drones can maintain extremely times on-station and the best part, they are much more affordable than the F-35. Ground forces are not to be outdone, robots now walk and look like men and pack animals. Meaning robots can handle rough terrain that wheeled vehicles cannot and again don't get tired (or want promotions or healthcare).
Despite those advances, we still pretty much remain focused on fighting asymmetrical threats with symmetrical forces. Despite being at war for over a decade, we still are using much of the same tactics.
It is unlikely that under the second Obama Administration much will change. There may be some increase tensions and perhaps some more air campaigns but in the end, nothing much is going to change.