They're not popular in Germany:
Cascada have a massive following all over Europe and are extremely popular but not in Germany - the Germans think that they are too anonymous! They don't think they will represent "the German sound" - they have a massive international fan base but not a German one, it seems... Germans feel they need to stand out - so I can't see Germany voting for Glorious.
Previous "big names" have failed in the German selection:
A few years ago Scooter participated in the German national selection, and failed, and also The Weather Girls participated in 2002. Two massive names in Germany and the world! But nether Get Up and Jigga Jigga made Eurovision - Why? Because the Germans don't tend to opt for big names like the rest of Europe would.
Personally I think Glorious is the best song in the German selection but it seems I'm in the minority... The standard is very high in Germany this year and the majority of songs are great! I believe Mobilée, Mia Diekow and Saint Lu could all be great German representations! They certainly will have to stand out if they want to win...
Germany will select their entry 14th February and 12 songs are in the running! ^^ Enjoy Glorious... Will it win? Time will tell...