What changes in Terra Incognita vs vanilla ?

While we do make some historical changes and try to bring a level of realism to the game we prefer not to label the mod; if we were to do so we'd call it a 'gameplay mod' more than anything else.

Overview

Realistic recruitment
Balanced combat
Balanced economy
New technologies
New historical units
All factions playable

Partial List of Features

Manpower and supply govern how many troops you can recruit.
Whole economic structure of the game reworked; unit costs, buildings costs, and more.
Research now costs as schools have an upkeep, whether they are researching or not.
Completely reworked morale system for both land and naval battles.
Completely reworked naval combat; turning, ranges, speed, acceleration, and a lot more.
Resistance plays a huge role and prevents steamrolling the world in most cases.
Tech tree and related research times completely reworked. Simpler technologies are easier to aquire, and some of the later philosophical techs will take some time to finish.
Removal of fire and advance and volley fire.
Artillery made much more effective; ranges increased based on shot type, accuracy adjusted with reload speed. Shots are much less accurate after 350 meters.
Infantry weapon ranges increased. Muskets do less damage at ranges over 50 meters.
Platoon fire now available only for Ferguson riflemen.
Tighter unit formations.
Light infantry doctrine and rank fire are lower in the tech tree and require less points to research than before making them easier to get earlier in the game.
All non-emergent factions playable.
Historical units - Potsdam Giants, Zeiten Hussars, Marines, Swiss Guards, Decanni Lancers, Douaniers, Regimiento Inmemorial del Rey, and more; more being compiled every week.
Balanced combat; Reload bonuses for firing drills are evened out, square formation more realistic, morale levels due to flanking and rear attacks more of a problem than before, units tire more quickly when running over long distances.
Light infantry now equipped with bayonets.
Experience caps (number of kills or deaths needed, etc.) lowered. Units gain experience quicker this way.
Fixed Taxes and other bugs that CA hasn't patched yet.
Revamp of Empire's numbers; Charge increased for cavalry and infantry; morale adjustments based on level of training, movement and morale on terrain or in weather, misfires, etc.
Redone/expanded descriptions for several units.
3 turns per campaign year.
Increased recruitment and build times to suit the longer turns.

New Land Technologies
http://i89.photobucket.com/albums/k2...loading_dr.jpg - Advanced Reloading Drills - Grants a 5% reloading bonus; grants access to optional Fire by Rank and Platoon Firing.
http://i89.photobucket.com/albums/k2...ve_firing_.jpg - Advanced Live firing Drills - Grants +2 Morale in battles; required to progress in the tech tree.

New Ordinance Technologies
http://i89.photobucket.com/albums/k2...dized_cali.jpg - Standardized Calibers - Precursor; required to progress in the tech tree. Requires Measuring Tools economic tech.
http://i89.photobucket.com/albums/k2...dized_ammu.jpg - Standardized Ammunition - Precursor; required to progress in the tech tree.
http://i89.photobucket.com/albums/k2...dized_prod.jpg - Standardized Production - Final result of standardization; reduced costs for all artillery. Requires Interchangeable Parts tech.
http://i89.photobucket.com/albums/k2..._artillery.jpg - Horse Artillery - Grants access to horse artillery. Requires Selective Breeding tech.

Community Contributions

Trasibulos UI, Naval & Land Flags (Republic/Monarchy) Retextures
MechDonald's Blood, Smoke, and Sound Mod
Captain Cox's Load screens
Remo's retextures
Sinuhet Formations
Waronmar's pipmod
Swiss Halberdier's AUM

More here;
http://www.twcenter.net/forums/showt...ads-Changelogs