Are any of your 'excellent' German records online? In the past few years an amazing amount of Irish records have come online- transcribed, indexed or scanned- census, church, valuation, etc.
Obviously the fire burning all the C19th census returns didnt helpAll the 19th century census records were NOT destroyed by fire in Dublin. The 1861 census, for example, was destroyed by government order after all statistics had been extracted. Remember that the purpose of a census is to count people not help later generations trace their family.
You haven't mentioned what religion your family were but it wasn't only Catholics that were penalised in Ireland- Presbyterians and anyone else not Church of Ireland (the Established or State Church) were at a disadvantage in earlier times. Ironically, many C.O.I. registers sent to Dublin for safekeeping at one time were also destroyed.
Many pre-1900 Wills were destroyed but the Will books do survive- both PRONI & NAI have put these online. However, many people don't realise that many of these older Wills were copied and survive in various archives.
All civil registration records (births, deaths, marriages) survive and before you complain that Irish registration started so 'late' let me point out that some places didn't register such events until the 20th century.
Interesting article about Romans in Ireland in British Archaelogy journal-
http://www.archaeologyuk.org/ba/ba14/BA14FEAT.
The lack of certain records does, however, probably make Irish researchers better at thinking about alternative resources when trying to gather information.