Your Internet speed has nothing to do with your internal network speed, so don't focus on it. Fast Ethernet (100 Mbps) is enough for everything but ripped UHD Blu Rays. And unless you're still on 802.11G for wireless (which maxes out below 50 Mbps), you shouldn't have any issues there either.
I'm home from my trip, so I've looked over the Panasonic profile closer. I've also downloaded the users manual for the BDT110. Frankly, it has very poor support. It appears to only support .MKV and .AVI containers, and doesn't provide any detail about supported codecs. However, since it plays DVD and Blu Ray discs, we should expect support for MPEG-2, H.264 and VC-1 video. But due to the fact that it won't play The Blind Side, which has VC-1 video, I expect their DLNA support is limited.
Looking at the current Panasonic BD Player profile, I would expect it to be transcoding everything that is giving you a problem. Since no DVD contains DTS-MA audio, it doesn't look for that. It does capture DTS-MA in the MKV container if the video is H.264. So it's working correctly with The Borne Legacy. What changed with your Handbrake version, I have no idea, but since the original plays fine, nothing to do there.
It appears your player has a bitrate limitation, as the profile author has all transcoding lines capped at 15.3 Mbps. That really seems low for a BD player, but I don't have one to test with, so can't experiment myself.
But I'm puzzled by The Blind Side. That should be captured by line in the last transcoding block. All I can figure is it's being missed for some reason, so let's try adding an explicit Matches for it.
In the Transcoding section, above the first "<Video targetContainer" line, add this:
- Code:
<Video targetContainer="mpegts" targetVCodec="mpeg2video" targetACodec="ac3" maxVBitrate="15360" DAR="16:9" maxWidth="1920" maxHeight="1080">
<Matches container="*" vCodec="vc1" />
</Video>
After you add that line, save the file and restart the Serviio server. Then see if Blind Side will play. If it doesn't, then I'm at a complete loss and it's time to think of something else to use as a player. Just be aware that your CPU will likely be maxed out, since you're transcoding video. I've had both a Panasonic BD player and a TV in the past, and both were less than satisfactory as a player for my videos via Serviio. Nothing Serviio can to to fix a poor DLNA player I'm afraid.