I do agree with those who say that, absent WW1, pressure will eventually build for some sort of naval reductions treaty, just because of the cost of capital ship construction. In addition the rise of other major naval powers such as the US and Japan would be seen as destablizing threats to both British and German calculations and the continued development of alternative naval systems such as aircraft carriers, long-range airships, and submarines (even without battle-tested doctrine) might lead major naval powers to question the investement thay are making in bigger and more costly capital ships.
That said, I think most weapons systems that were developed in WW1 would still be designed and developed. The difference would be the development of doctrines for using them, many of which only can be evaluated in battle. This would affect the nature of how and when these weapons were introduced.
I think armies would become mechanized just as quickly as OTL (which really wasn't all that rapidly anyway). Motor vehicles would still be developed and improved and anyone would see that trucks, cars, motorcycles, and motorized gun carriages would eventually supplant horses for for military purposes.
One big difference, is that absent the experience of WW1 and its demonstration of the effectiveness of machine guns, military doctrine would remain more focused on mobile warfare, with horse cavalry being supplement by motorized infantry carriers and armored cars. The whole doctrine of trench warfare and the human cost of offensives would not have been shown
Tanks (armored mobile gun carriers to support infantry) might not initially be the massive, slow behemoths deployed to break thru tranch lines, but be smaller, more agile light tanks.
Technologically, aircraft development would still be driven by commericial factors, so the basic technology or airplanes and airships would develop in a similar manner as OTL, although with some detail differences.
However, with no aerial warfare examples existing from which to develop doctrine, I think most militaries would not have incorporated aircraft as offensive weapons to the extent in OTL, their main value still being seen for reconnaissance, scouting, high speed transport, and limited bombing/harassment of ground forces. Once it becomes apparent that aircraft will be fighting each other to control airspace above the battlefield, my guess is aircraft designers and militay leaders will flounder around a lot longer than OTL before settling in on the single-seat tractor biplane as the ideal fighting plane. Expect to see a lot more multiplace and multipurpose warplanes intended to fight with multiple gun batteries, rather than "fighters" that use their guns by aiming the entire airplane at the target. Perhaps the whole notion of synchronizing MGs to fire thru the propellor disk might not occur to people without the experience of aerial combat in WW1.
I also think the development of really high-altutude aircraft will be retarded considerably.
Airships (both non-rigid and Zeppelin types) will probably be overvalued for their extremely long range and high endurance, leading to their retention far longer as naval scouts, anti-submarive pickets, and perhaps long-distance transports.
Fleets would incorporate aircraft carriers about as early as OTL, but with a doctine aimed solely on extending the long-range recon of cruiser divisions and tactical scouting for naval gunfire. Paradoxically, because a premium would be on smaller airplanes for shipboard use, navies might actually lead the way in developing compact high-performance aircraft such as single-place tractor biplanes.
I think submarines are a real wild card. Absent the specific example of Germany deciding to turn to unrestricted submarine warfare to counter the British blockade, the notion of using submarines primarily against merchant shipping might not occur. Submarines might still be seen primarily as coastal craft - with perhaps some larger types developed for use as naval scouts, pickets, and so forth. Since the presumtion would remain that any use of submarines against commerce would abide by existing prize rules, any submaines intended for that purpose would be large "cruiser" type boats, optimized for surface combat and handling prize crews and captives.