We know they're adding 27 units and 9 civs. So 9 of those are most likely UUs for the new civs. The Pictish Warrior is most likely one of those UUs. We also know there are at least 2 new great people, the Great Prophet and Great Admiral. We also know there's a new early tank, triplane, biplane and machine gun. So that's 15 of the 27 new units, leaving 12 more. If there is 1 new naval melee unit for each era, that's 6 new naval units, leaving another 6 units. If the Machine Gun is in the upgrade path for the Archer and Crossbow, there's likely a Renaissance unit, such as Civ 4's Grenadier between the Crossbow and Machine Gun, leaving another 5 units.
Those last 5 units could be anything such as a 2nd UU for up to 5 of the 9 civs, a Great Spy, special units for the new scenarios, or just regular units added throughout the ages. If they are regular units then it stands to reason that the combat strengths of all units would be increased up to 2x the current to provide better gaps for those remaining units to fill, which would explain both the Pictish Warrior's strength while researching iron working and the machine gun, an industrial era unit, having strength between the mech infantry and modern armor, which are both modern era units.
This also indicates that we most likely will not have units for spreading religion like we did in Civ 4, because we'd need 11 units to spread all 11 religions, because they'd have to add at least 33 new units not just 27.