DLC which isn't really worth the price tag which is asked for except for the maps.
Pro
-Adds two new civs in a region which already features most of the civs in game making them feel like redundant additions.
-Features a lot of new maps so that you can colonize (sorry, I meant explore) Europe.
-More hunting grounds for Gall. Those reactionary monarchists with their ridiculously looking wigs and pale faces will have to face the fact that they don't look as fancy as Gall. Wakan Tanka will follow you on your quest.
Contra
-Civs are from a region which already features most of the civs (11 out of 22 excluding European descent civs like USA and Mexico but including Ottomans) making the game's faction feel more sameish.
-Malta, as a insular microstate, really doesn't feel like it does belong in Age of Empires. Even considering the Mediterranean theme, it would have been better to add the Barbary States or Morocco, as their regional importance was on a considerably bigger scale than Malta. You might argue that Malta is part of the AOE3 campaigns, but using this argument, you could argue for the Circle of Ossus and the Black Family as distinct playable civs which would be just stupid.
-DLC doesn't feature new architecture sets unlike "The African Royals" for which the same price is asked. With the US and Mexico DLC, it was half excused as Mexico resp. the USA civ were basically revolution civs made into full civs and considering the fact that they were both smaller and cheaper DLCs. Some AOE3 mods like Wars of Liberty did take the effort to create brand new architecture sets for their Anglo respectively Latin American civs they added. That the official Age of Empires 3 devs don't put the same effort in the game than fans is pathetic but not surprising considering what they're also doing with AOE2 right now.
-Would have been better to add Morocco instead of Malta as they're a bigger player (metaphorically and literally speaking) for the Mediterranean region than Malta whose only notable achievement was resisting against the Ottoman expansionist plans. Morocco were anyway half done for African Royals and it would have been the perfect DLC to introduce them in my opinion.
-Reusing of original campaign assets instead of creating completely new ones.
-Reusal of voice lines from AOE2 instead of creation of new ones. Compare for example with African Royals in which they took the effort to record almost all voice lines for the new African natives and units.
-Explorers and profile icons which you missed as you didn't have the time to play when the event was live are out of reach forever. Devs inciting FOMO (Fear of Missing Out) are crap.
-No new music
Not really interested in playing Tycoon mode or the historical maps as scripted battles nor the setting really interest me.
TL;DR: Get it on a step sale if you really want to play on European maps. I wouldn't buy it for the factions if I were you. Hope that the next DLC adds something else than more of the same. More civs using "The Asian Dynasties" mechanics like Koreans as well as more African and Native American civs would be welcome. The framework of AOE3 is even more ideal to add Oceanian civs than AOE2 to add civs like Maori so those would be welcome too. Age of Empires as a franchise as a whole focuses a bit too much on European civs for my taste right now. A course correction to civs with a bit more varied cultural backgrounds would be very welcome, as I don't really think that it's necessary to have 3 different flavours of Italian civs like it is the case in AOE2 as an example.
EDIT: Guess what, there's now a Danes/Poles DLC announced. What a crappy move from the devs. Not going to give my money for something which feels completely unnecessary.