What do you mean by, "how to deal with them"? How to build walking war machines? Or how to find a Traveller equivalent that will serve your characters while being true to the Traveller ruleset?
Walking war machines in the Traveller universe are the next best thing to the Maginot line. If you want put your players in something suitable for a Traveller setting, go with Aramis' suggestion and put them in grav tanks - they're the knights of the Traveller setting.
If on the other hand you actually want walking war machines in your setting, you're going to have to house-rule in some changes that turn a walking bullseye into a believable fighting craft. First is you probably need to abandon gravitics. Trav gravitics allow an enemy to be both heavily armored and jet-plane fast, allowing him to bypass your walking armor and go wreck your rear lines. To justify a mech, you need the enemy on the ground with you or flying in things with wings and little or no armor.
Second, you need to make standing tall in a battlefield something less than suicidally foolish. One idea - almost a must - is a mech-size nuclear damper to keep this thing from being an obvious target for a mininuke. Another might be very good point defenses, so the thing can't be stopped by any infantryman hiding in a foxhole, or maybe a magic-tech force shield, something that limits threats to heavy weapons and maybe needs a big machine to carry it - so it justifies having one big thing on the field instead of many little things. Think Martian War Machine, 2005 version. The challenge here is to find a way to defend the thing while at the same time leaving it able to fight an opponent similarly defended.
Third, you need to ask yourself why you're building a thing that stands tall in a battlefield instead of building a thing that hugs the ground making itself harder to hit while letting an expendable and much-harder-to-spot drone do its high-level observing. That one I don't have an answer for. The Martians in my above example expected to fight a foe that couldn't hurt them - ergo no reason to stay low. Maybe weaponry is so precise that anything that doesn't have a shield is doomed, and the only things that can carry a shield are too heavy for flight, so standing up in a shielded machine is the only way to get a good view. Of course, that leaves you with the problem of extremely precise weaponry, something you might not want.
Mechs are fun, but it's challenging coming up with a setting in which they're actually a reasonable weapons platform.
Transformable Mecha is the Ultimate Warmachine.
- Flies like a Jet Fighter getting to places at Supersonic Speeds; and, using Long-Range Missile Systems for hitting Targets that are Beyond The Horizon.
- Walks like a Human; and, using Large Caliber Guns for Line-Of-Sight Combat; which, is ideal for Street-To-Street Fighting in Urban Warfare Situations.
MECHA TECHNOLOGY
With Modern Day Sciences & Technologies, Mecha isn't a viable Military Weapon Platform.
Your arguments seems to be based on Real Life Modern Day Warfare and Real Life Military Sciences & Technologies. In which case, a Modern Day Mecha could be easily taken down with Real Life World War Two Infantry Weapon Systems.
Sci-Fi Mecha have Armor that Real Life Infantry Stinger Missiles can't even scratch the paint off; and, Real Life Infantry Stinger Missiles can take down a F-16 Fighting Falcon flying at high altitude.
Sci-Fi Mecha have Armament compariable to Modern Day Battle Tanks and Modern Day Naval Frigates.
?Who wouldn't want a Walking Armored Battle Tank armed to the teeth like a Naval Figate?
I have created a
BattleTech 'Mech that was faster than the LCT-1V Locust Design; and, Locusts are the fastest Published 'Mech Design in 2nd Edition
BattleTech &
MechWarrior RPG.
LCT-1V LOCUST
- Walking MPs = 8 * 30 Meters = 240 Meters/10 Seconds
- Running MPs = 12 * 30 Meters/Turn = 360 Meters/10 Seconds = 129 km/Hr = 80 MPH
MST-1 MONSTER (my own
BattleTech Mecha Design)
- Walking = 1 * 30 Meters/10 Seconds = 12,800 m/Hr = 8 MPH
- Running = 2 * 30 Meters/10 Seconds = 21,600 m/Hr = 13.5 MPH
- 6 PPCs (lost Hand Actuators) + 30 Heat Sinks + Maximum Armor + Small Laser + 1 Jump Jet (needed for climbing hillsides)
