Actually your link shows that the effects were not as bad as stated. In any event, with no American Involvement, the Cargo Subs make more journeys to the U.S. and the German people with the defeat of Russia see the light at the end of the tunnel as no American intervention means they aren't facing yet another foe.
Frontline forces also get a boost because they will be receiving much needed reinforcements.
By Fall 1918 the Ukrainian Breadbasket would be coming in full tilt, relieving much of the strain.
The blockade was been argued to death and I have read both sides of it; the case against for the blockade being the real cause of the collapse on the home front that seems the most credible comes from this work:
http://www.amazon.com/First-World-W...=sr_1_1?ie=UTF8&s=books&qid=1282493097&sr=8-1
The author, while making an interesting case, extrapolates the experience of the entire country from the records of Hamburg. Its a flawed methodology at best. Germany was suffering from shortages of every kind, food being the worst of all. Mismanagement was rife, as was profiteering and blackmarketing. Things got so bad that lead pipes had to be used for city drinking water!
Ukraine turned out to be much more trouble than its worth, as even by the armistice it had not produced food beyond supporting the occupying soldiers and in an "America never joins the war" scenario, it probably would never have been under CP occupation.
If the US doesn't enter the war, assuming a lot here just on this POD alone, then Russia is going to leave the war earlier. That means no Brest-Litovsk, because before the CPs started playing hardball by annexing all of Eastern Europe, they did not want to occupy Ukraine. So by 1918, assuming the war is still going on, which it probably would not be, there is no CP Ukraine, which paradoxically actually makes the CPs stronger militarily and politically for reasons that are too in depth to cover right now.
Honestly, the loans issue is what will knock Russia out in mid-late 1917. If the US is not making unsecured loans, the French and British cannot make loans to Russia, who will not be held hostage to her Western Allies' interests and also cannot finance the war. The Entente also no longer afford to send Russia materials of war, which, when coupled with internal instabilities, means Kerensky and the provisional government will have to drop out of the war. They will have no reason to stay in, no matter how much the army may want to. This means to Bolsheviks either.
Without the US, then the blockade is more leaky and may turn into a major issue with the US, as without the Entente orders rolling in, primarily thanks to no more US loans (secured loans cannot be financed by France or Russia...the British will have to cut down on loans as well), a new market will need to be found, which means the blockade my become a major political issue, as business will pressure Wilson to force Britain to back down.
Furthermore, another major part of the blockade will collapse without American financing: purchasing. The British were able to enforce the blockade partly by buying up useful war materials so that transshipments from countries like Denmark and Holland cannot be made. If the Entente needs to focus funding exclusively the war effort instead of denying Germany resources, more goods can start to be transhipped. It will be a trickle, but more than Germany had before.
Furthermore, the triple hit of the US not entering the war/cutting loans, Caporetto, and Russia leaving the war early will have a massive effect on the Italian and French political scene. Italy may ask for an armistice in the wake of Caporetto, which will nearly guarantee France will ask for one too. Its all speculation and is not guaranteed, but with all these things coming together, I am willing to bet money that the warring nations will come to the negotiating table in December 1917 or January 1918. Germany will be launching offensives to support her position at said table, probably similar to Kaiserschlacht, which, if panic occurs among the Entente leadership something like OTL, will mean a better peace for Germany. Not a full win, but a victory nonetheless.
Also, I doubt that Clemenceau will become the French prime minister in 1917. Without the US in the war, loans cut off, and Russia out earlier, Joseph Caillaux is probably going to be named instead with a mandate to negotiate. France is probably going to have different expectations than OTL 1917, which means less will to conduct even limited offensives, which won't be able to be financed (the extremely prodigious use of artillery shells at Verdun in 1917 won't be affordable, nor will the French army likely to be as willing to go on the offensive, as THE most major component of Joffre's rehabilitation program was telling the soldiers victory was guaranteed if they could simply wait for the Americans to arrive, which won't be an option here. Source:
http://books.google.com/books?id=vZ...&resnum=7&ved=0CDwQ6AEwBg#v=onepage&q&f=false), making them more willing to negotiate. Plus, without Clemenceau's 'brutalization' of French politics, i.e. demonizing the peaceniks and jailing their leadership including Caillaux and charging them with treason, the French home front, already wobbly as hell, will likely face a German-style 'stab in the back' collapse, as without hope, peace, even unfavorable, will be seen as necessary. Again source:
http://books.google.com/books?id=vZ...&resnum=7&ved=0CDwQ6AEwBg#v=onepage&q&f=false
No US means very likely German minor victory. No Brest-Litovsk, however, CP Kingdom of Poland. More stabile Austria-Hungary than OTL (long explanation there), but it military oppression will keep it together and expect Karl to screw up the post war. Half of German colonies returned mostly in West Africa (horsetrading), though Belgian Congo is picked up and probably some French colonies too. Belgium itself is not annexed, though I could see the customs union being a compromise that means it is defacto a German economic satellite.